First of all, no, you are not too far gone if you are still feeling anything at all.

Second, you are clearly intelligent and articulate enough to express your feelings, however unpleasant.

Third, don't give up on yourself. I speak from experience and a much worse place in many ways. I really do understand.

Perhaps you can refocus your energies on your kids and their success & then on yourself. You can start preparing yourself to work, if work is what you want to do. It will be a way to gain a measure of independence too.

It sounds like you are helping your H ...do school work? IMHO I would Stop That right now. You are making things too easy for him and he is letting you. If he fails his classes, ....what is the consequence? If he is unable to do the work required, then he needs to be a man, go to the counseling office and figure out what accommodations he needs to do this on his own. It is his responsibility. He is treating you like his mommy.
If you do Everything else, so that he can go to school, he needs to go and perform like the rest of us. Don't give him a free ride on your back. You are doing him no favors if all he has learned is to manipulate you into doing it for him.

And of course there is no sexual feeling. Between his meds and the role he has cast you in, mommy, that would kill even the strongest sex drive.

Don't give up, you sound smart and very capable, just beaten down right now. You are not alone! Many of us really do get it, and struggle with some of the very same issues. Keep writing. I'd love to hear how you are doing... Women need to stick together in these trying times.