Hello Eamgr: Oh yes... there is apparently research I've read about that suggests childhood bullying continues to affect a person well into adulthood.

In fact, I read one article (I don't recall where) that said being bullied by one's peers during childhood is more damaging than being abused by one's family members. I don't know about that one in particular. But you get the idea.
I was bullied both verbally & physically throughout out junior & senior high school by a gang of older, physically larger boys. The circumstances were such that I could not escape. Everyone, including my parents, knew what was going on. But no one helped. At one point, one of them beat me up breaking my nose. I got blamed for it.
I'm 68 now. I don't know if these experiences caused all of the mental health problems I've had over the years.

But they certainly didn't help. At this point in my life I live as solitary a lifestyle as is possible. I simply want nothing to do with anyone, in real life, any more than is necessary. I'm glad you are finding some degree of success in becoming more social & gaining some close friends. I wish you well...