(Probably terrible advise!)
Honestly, I don't have great advise for you since I'm pretty much in the same boat, I'm a loner. I have a few acquaintances in real life that I never talk to (about personal matters at least), and I've never had internet friends before. Though I've never particularly felt lonely.
I apparently have somewhat of a sociopathic streak, which has caused plenty of problems for me in the past (I even managed to get estranged from my only sibling when I was a teenager, and recently even my niece), so I decided to act like what I think is a perfectly normal outgoing person when I got into high-school because I felt it was the sporting thing to do. This was fine at first, I was very good at it if I say so myself, I made quite a few friends and even got myself a girlfriend or two, but things always crumbled when intimacy made me let my guard down. Especially since, lets say, my interests and opinions on popular events and culture aren't safe for mainstream consumption (whatever that's supposed to mean), and they just kind of slip out sometimes, as well as the fact that sometimes I appear hostile even when I don't mean to.
I mean, I have acquaintances from my time in University and from work, and but none of them have actually seen even a micrometer of what I actually am. They think I'm a mature,kind, productive and reliable member of society, which I'm not. I also often forget about them so I'm not always the most reliable or sociable friend. While I'm not the most sociable person ever at work, the results I provide more than earn my right to stay at my workplace (god knows some coworkers won't be able to survive without me), and I'm never unpleasant.
But after pretending to be someone I wasn't, I just noticed that it wasn't really worth it, I decided extended physical socialization isn't for me and reduced physical socialization to a minimum(which is a terrible thing to decide, you shouldn't decide this). I decided I'll get my genuine social interaction from helping people online instead, where they won't be around for long enough (or interact sporadically enough) to begin being strained by my terrible personality. If I do things right even someone like me can get a thanks or two (which can be immensely fulfilling), or maybe have a intelligent discussion about something.
(TLDR) By god, that was long and dubious in direction. What I want to say is, don't strain yourself, we all have our pace. Someday you'll figure out our social sweet-spot and be perfectly happy sitting in it. It may not be what you envision now, but it'll be sufficient for you. Try new things is GOOD! You know, gym, the local Cabaret, shooting range, tech support on this forum, sh*tposting on a futa hentai reddit, whatever. But don't force yourself, don't rush, there's no point if you're battered and bruised by the end, because someday you'll find your place. And while you find that place, this forum will probably do, hell, maybe you've already found your place. Though I guess as a conventional biological organism you'd be lonely without a mate, and you can't mate with the internet... I hear most mate with the most agreeable person at their workplace, so that may be a good place to start.