Welcome back shmiras!!
I don't remember you, I'm only here about 10 months myself. It's awesome that you came back, and are looking for help!!
You're story sounds extremly dificult, but one thing that I can relate with is feeling distanced from Hashem, feeling undeserving, and all the other self-denegrating feelings.
In a way those feelings used to actually save me from severe depression, for they told me that I was still upset about those things, whereas others didn't even care about them anymore.
But on the other hand it was all a mistake.
What it really was was that I wasn't ready to open my mouth and hear what i was going to say. I wasn't ready to accept myself, to accept who I really was. So I silenced the pain with saying that I was still ok because it bothered me. If I would have told myself that Hashem loves me and accepts me the way I am and that I can talk to Him without anything in the way, then I would have had to accept myself as well, and dealt with it. One thing I found is that I can always
talk to Hashem no matter where I am at.
If you were indeed able to stay away from all lust during your yeshivah days, then it may be that you never really accepted the fact that you have a serious problem.
Have you opened up to anyone?