I feel like I'm everyone's b-tier friend

(19M) I have a couple of friends (none of them are friends of each other btw) . I feel like I never get invited to fun activities. If we ever do something, I initiate it. When they do a fun activity of which I would like DIE to be there for I'm just outside of being considered to be invited and it makes me feel like shit. I hate it. all I see all week is school, work and my room. Nobody asks me how I'm doing, Nobody seems to mind my absence. When we see eachother, it's because it's school or work. It makes me feel like nobody would miss me if I was gone, because i'm not there in the first place.