Yes 95% of your friends aren't your best friends. They have their own struggle and hardships to deal with. So yes, in your situation both side needed to focus on themselves.

Lastly before being worried about the general population not including you in their social circles, did you ask yourself why you would be in their circles ? Because you were colleagues ? Or neighbour. I also am in a situation were I have virtually no friends and it fucking hurts. Loneliness fucking hurts, it ache the minds and psychology its among the worst pain I ever felt.

Though in the past years I've looked not for others but for things that passionated me first. And there I found people which liked me and that I liked. Some people are wildly different than me, others are likeminded but we connected. I don't know my classmates but I have a few friends among my martial arts club. And I am not unhappy of the lack of connexion I have with my class, I don't think we'd really fit. Despite the social constructs that claims a student's first circle must be his class, I don't, and its fine, I just look elsewhere for people, in place where I fit.