I recognize some things you describe. Some things with you are more extreme, others are more extreme with me.

I don't know how I myself really got out of it. I stopped going to college for 9 years. Then slowly got back into it at age 29. I didn't like other people. I had no goal in life. I didn't care to be popular, rich, respected. I was passive, avoiding, didn't reach out to people. If I wasn't going to be a guaranteed winner in life, be it career, friendship or romance, I wasn't even going to try. You can't fail if you don't try. And I wanted some special kind of life few people have. I couldn't imagine myself living an average life.

As a child I never skipped classes in school. I guess I didn't dare to; it wasn't proper. But after I switched to my second college, it became so easy not to go. And I didn't go to hang out and have fun. I didn't go so I could be alone, or to obsess about my intellectual interests. I was terrified by the idea that being lonely didn't terrify me, because that meant I would never act to not be lonely because of the discomfort of loneliness.

I was never really depressed, except for a few months. In the end, the pain of depression is what got me out of my comfort zone. But I was very anxious and I constantly worried and puzzled about who I was, what my life would be like in a few years, and what was wrong with me causing me to have no place in society.

I never talked with anyone about my feelings. My parents have problems of their own. My mother has been too weak to give any support at all. My father would just yell at me for being a failure, though he would support me financially. My father must be high functioning autistic, maybe like me, maybe like my mother. My brother seems normal, but he must be damaged as well. Me and my brother, we do not talk about things. Actually, my brother barely talks nowadays. Not even with his girlfriend.

And of the two friends I thought I had, both lived far away from me, and one was female (me being male) and I was obsessively in love with her. The other friend, I didn't want to burden with my problems. He was graduating, living an active life, and I was nothing. I didn't think he would respect me. And I didn't want his pitty friendship, which he at some point bluntly offered to me. He bascially said, 'I have another loser friend and I am staying friends with him', 'you can be my second loser friend'. We came back in contact 6 years later.

After 9 years of nothingness, I went back to school, then to university. I am doing really well. I cannot explain how. I shouldn't be able to do so well. I always performed below average throughout my childhood. I think it might be a desire to be really smart combined with some Asperger traits. I still fear I only am high-functional in the academic sphere because I neglect all other spheres. And yes, I still have problems there. Though I am supposed to be reasonable attractive, my experience in romance is flimsy. It confuses me, pains me. I thought no romance happened for me because I never met anyone. Now that I meet some people, probably still to few, I don't see any paths to romance. I thought I saw one path with one woman, and I tried to avoid mistakes I thought I made in the past, but it ended up me getting hurt maybe more than I got hurt as a teenager.

I also make no friends. It may be because I take no risks. I don't make the first move. And I try to project myself as being confident, all-knowing, succesful, strong, reserved, composed. Maybe people quickly realize that I am not being myself. Or maybe I give off a wrong flavor, making me appear arrogant, unkind, aloof, calculated, dishonest.
I don't try to make friends. And I have a hard time small talking. When I see others talk, often 10 years my junior, I can't relate to what they are saying. And it is not just the age gap. And all my jokes seem to fail. It is also really hard to think of something witty, then feel comfortable enough to just say it. So I never do that.

You should seek professional help. And you should tell them the truth. You say you tried, so I don't know how you can change that.
Your studies being difficult, I guess that's natural when being depressed. And naturally, people don't gravitate to depressed or awkward people. When they have a hard time making friends as well, they rather not try it with someone despressed or awkward.

Everything is interconnected, which makes it hard to get out. Especially if you can't think in terms of babysteps. Maybe the mistake I made is to shoot down every positive thought I had, because it wasn't a solution to all of my problems.