I have basically two states. (I've mentioned this periodically in my posts & replies to others' posts.) One state is what I call: "dull acceptance". This is where I am most of the time. It's just sort-of a state where I say: "Oh, f***. This is just the way it is. There's nothing that can be done & no one really gives a rip anyway. So just suck it up & move on. It's not so bad."
The second state is: "I just can't stand this for another minute!" I go in-&-out of this state multiple times per day & / or per week depending on a variety of variables. This state has landed me in the hospital twice. And, you're correct. They were the most expensive & most useless periods of time in my life.
I wish I knew of a surefire cure for this. But, of course, I don't. This is probably because there is none. I don't have a therapist. I've tried therapy & it always seemed to be almost as useless as being in the hospital. I do have a pdoc. And I take Cymbalta, which seems to help a bit. Otherwise I try to employ the practices taught by the Buddhist nun Pema Chodron. They're not a cure-all. They're not meant to be. But they do help.
I'm glad to hear you're not going to give up, Regretful. I do believe you can get through this. Just keep trying different things until you find what works for you. Then come back & share it with all of the rest of us here on PC. My best wishes to you!