Downloaded this to rant about how alone I feel socially

Man it just sucks when your the person everyone forgets, multiple friend groups over the years, and the recurring theme they all hangout and conveniently forget me. Many times I'm just alone, I've gotten use to it at this point, but man it feels so glaringly sad, like a lot of self pity of my situation, I feel so much more alone after ending a relationship/situationship like damn am I really this alone in this world, I didn't really care when I had someone to talk to but those gaps when im single it just me, and even if it's a little cringe the gym is the only place where I interact socially with a lot of people, I put on the facade of being content with my life to those so called friends who leave me out of everything, but sometimes I just wanna do a fresh start but then again it has happened many times what's stopping it from happening again?