I (20m) haven’t had friends since 9th grade and i don’t know what to do

So I suppose I’ll start with an autobiographical section before getting to where I am today. Hopefully this won’t be too long. I’ve been in a pretty bad depressive state for the past few months, and it stems from my loneliness, as well as a fear that I will be unable to change it. I haven’t had any irl friends (I have online friends) since 9th grade (late 2016), and that’s obviously extremely abnormal, and the length of time is one of the things that makes it feel impossible for me. I used to be of the belief that it was just social anxiety that caused this, but upon closer examination I think that that’s only one aspect of it.The main thing that’s been on my mind lately is that I don’t share anything in common with anybody anymore. Back when I did have friends, we would take about typical 13 year old boy things like video games, youtubers, just whatever right. Well since 9th grade I’ve only had 2 real interests that I’ve spent almost all of my free time on, music and later on politics. I know that these aren’t exactly obscure things, but nobody wants to talk about politics all day, and when I say music I mean listening to multiple albums a day every day. I’m completely out of the loop on things like sports, movies, tv, books, video games, etc. I feel as if I’ve been living in a different world to normal people, and don’t know how to converse with them because we just operate completely differently.These years of isolation have impacted my social skills pretty badly too. I go silent in groups because I never have anything to add, I never start conversations (only ever responding, I just can’t think of something to say), I feel like I’m too short and blunt in conversations, and obviously my anxiety is quite bad. I can’t keep a conversation going without losing steam after 5 minutes or less.

I’ve considered the possibility that I may have aspergers / autism, AVPD, etc, but I obviously can’t diagnose myself, so when I start seeing a therapist (next month) I’ll ask to be screened for that stuff.

I just feel so stuck right now, and like I don’t know how to reintegrate myself into the world, or where to even begin. I think I have to expand my interests, but I don’t really know where to begin, and feel like I’m floundering around aimlessly in that regard. What would you recommend? My idea has been to just try and catch up on tv, movies, video games, etc to the point where I’m conversational and knowledgeable about them, but that will take an extremely long time and probably just drive me insane. I also know that people don’t just talk about that stuff all day, but like I said I don’t even really know where to start, and don’t know how to get into the same “world” as other people so to speak. I also don’t know how to stay in a steady habit of using my free time in a way that leads to things that people can relate to and are conversation topics. I often just do nothing all day, which doesn’t help. What are like, 5 things I could start doing that would give me something to relate to people on?

I’ve also been struggling with feelings of worthlessness, and that there is something fundamentally wrong with and offputting about me. Nobody in 6 years has seriously wanted to be my friend. I know that’s partially on me for being closed off and isolating myself, but still that’s quite staggering to think about. I worry too that if it is indeed possible for me to reintegrate myself, it will take an ungodly amount of time to do so. I really feel like I’ve ruined my life, and it’s over before it truly began. I can’t connect with anybody because I’m just not on the same wavelength.