Your main problem is one of identity. You've attempted to change your identity from Christ, to take on a new identity as an ego.
Your sense of your "Self" has become associated with, attached to, and confused with, an alternative model of identity.
The ego is nothing but a device, a contraption you invented like a vehicle. It's something for you to cling to and to try to model yourself on. It does absolutely nothing on its own. It is lifeless.
It's not until you attempt to become joined with the ego, as though becoming one with it, that it becomes a problem.
If you think of it as a costume (like the body), it's not until you actually wear it that it seems to change how you express yourself.
Or, like a pair of goggles, it's not until you put the goggles over your eyes that your perception is changed. You can put them down again at any time and immediately resume normal vision.
You, as a Child of God, bring your sense of Self with you wherever you go. Your Self is your identity. The ego has no real self at all. However, if you bring your sense of Self to the ego and merge with it, you combine your sense of Self with its way of filtering reality. You then see "through" it, and see in the way that it would see if it had its own ability to see.
It is only your own ability to see - awareness - that you combine with the ego, that seems to give the ego perception. It is only your own ability to experience - being - that you combine with the ego, that seems to give the ego the ability to experience. It is only your own power which you share with the ego, which seems to give the ego power. It only shares any of this with you while you are joined with it, and as soon as you take it off, it would just drop to the floor lifelessly. Just like the body.
The problem is, when you've put your ability to experience and your sense of Self into the ego, trying to cling to it tightly as though making you become like it, you will now experience life through its eyes. Whatever it sees or how it looks at things or what it wants or how it values or what it believes, now becomes your experience. And you will see reality as very frightening when you look with the ego!
That's a problem because the ego's way of looking at reality is completely backwards. Seeing life through its eyes you will instantly reject God. God will suddenly seem to be an attacker, an enemy and a threat. The truth will suddenly seem like it is against you. The truth will come across as being the complete opposite of what you are, because it does not contain any separation, and the ego identifies with being made of separation. So the truth will then seem to be an affront, highly offensive, dangerous, hideous, and like some monster come to destroy the ego.
You, as immortal spirit, using and attached to the ego, ... if you attempt to become more spiritual while still wearing the ego identity, ie still joined with the ego mind and still looking through the ego goggles, will have a pretty interesting experience. You will not want to wake up. You will see any efforts to wake up as harmful and hurtful. You will interpret efforts to wake up as suicidal and sacrificial. And you will become afraid that the truth is coming along to destroy you. This can potentially provoke you to put up defenses against the truth, producing sickness and ultimately death.
This is precisely what you will experience each time you try to open up to more truth. Each time you let in some light. Each time you want to become closer to God. You, attached to the ego, inadvertently try to bring the ego into that light with you. It cannot go there and it won't go there. It will see it as you trying to destroy it. And it will put up a fight. Part of you which seems not to be in the ego gets closer to the light, and the part of you which does not want to let go of the ego - believing it is your Self - kicks and screams and resists and hates you for it.
This produces the ego rebound. Essentially, the ego rebound comes from trying to make the ego more spiritual, by attempting to bring it closer to its opponent. While you are identified with it, your attempt to go visit God without leaving the ego behind will create an elastic effect which will snap you back into the body and you will subsequently rage because of how you did such a horrible thing to your "self".
Waking up must entail the letting GO of the ego, recognizing that it is not your identity. Otherwise, each time you pull your "Self" into the light, and thus the ego with you, it's going to hurt. The ego cannot see the truth in any other way. It only sees the opposite of the truth as being true. It will never change. The ONLY way to be free of it is to let it go, to stop being it, stop wearing it, stop looking through it, and stop using it. We have to learn that the ego is NOT our "Self".
So this is purely a matter of identity. Are you made of ego? Is your Self really separate from God? Who are you? Are you Christ? Are you a body? Are you part of the ego thought system? Are you made of sin and guilt and fear? Do you believe in what the ego believes in? It's only because you have become CONFUSED about what really is YOU, and what is the ego, that you are having to go through this struggle of "awakening'. You literally believe, through the ego, that you are trying to destroy yourself by waking up.
Sometimes when you are exposing yourself to "too much truth" or "too much Course", you'll have these ego rebounds. You kind of can't help it. You are still holding on tightly to the very thing which is clouding your judgement, while simultaneously trying to be free of it. This makes you torn. Trying to be in two thought systems at once, or two canoes. There is part of you that sincerely believes you are the ego and you are the body. The suggestion that these things don't exist frightens you.
Letting go, letting go, letting go. Stopping being ego. Surrendering the false identity. Remembering who you really are. Accepting the truth that you are Christ. Relinquishing your belief in, trust in, faith in, confusion with, and reliance on a false self that isn't really a part of your identity. You literally believe the ego is who you are. It's not. Just some clarification needed. Some discernment. Is this really true about who I really am, or is this just a misperception caused by me using the ego goggles? Is this really who I am, or is this just a body I'm wearing temporarily?
Sorting out "who you are" is what this entire process is about. Each effort to "find out" will likely be partly fruitful and partly self destructive. Each time it will potentially offend you. Gradually you will inch towards awakening. Jesus says, "most of you will come in tears".
Each time you have a rebound, try to focus on LETTING GO. Just stop to recognize that you - part of your Self that's still identified with the ego or body, has become deeply hurt and offended by what the truth said about it. IT believes that the truth is vicious and mean and disrespectful. It is scared and freaking out because it doesn't understand what the truth really means or implies.
It, seeing through the ego, sees your efforts as blasphemous and an attack, and so it feels attacked and guilty. And that's what you'll feel like when you get a rebound - attacked and hurt and guilty. Recognize that in you and have compassion for that part of you. Try to get that part of you to let go of being ego.
Try to reassure your "self" that the truth doesn't mean YOU don't exist because YOU are not the ego. Be gentle with that part of you which is just like a confused wounded animal in the corner. Be kind to it. Don't push it too far too fast, that will just hurt more.
Likely you will have to feel the feelings of the hurt that was created by "its" mis-perception of what you did. Your attempt to wake up was like an abandonment of the ego self, like a self sacrifice. It doesn't have the ability to see any other way. So take your time and rest and recover and stop pushing yourself so hard.
Gradually and gently you need to learn to just LET GO of the ego because it is not who you really are. What you'll learn about your real identity is going to be quite a surprise!