You sound either burned out or depressed to me... The feeling of being "dead" is common among people who are exhausted or depressed, or both. Or under a lot of stress.
What you did, you did to protect yourself. Keep your head down, and you won't get harassed. That's a legit strategy; even smart. Took a lot of self-control, probably.
I think you should find a place where you can be quiet, but still be with people... doing things together, maybe. Hobbies? Volunteer work? Whatever, just find something that'll let you have quiet company. Sometimes it helps to hang out with people much younger or older than yourself. Find a place that's safe, where people won't harass you, and you can start reaching out again.
It's no wonder you stopped interacting; anybody would, if every time they tried they got abused by the local bullies. Hope you find some people who aren't bullies, and find the courage to take a chance on interacting with them.