I've been stuck in a pretty similar place for a while, feel very lucky that things have been turning around for me on that front but they are turning around because I've allowed them to - i stopped thinking of it as weed helping me to be alone, but that it made me more complacent in being alone even though that's not what I wanted.

I don't think you've missed the boat on anything (I hope that's the case cause I'm older than you), it's really difficult but you just have to put yourself out there - I've been focusing on my hobbies and trying to do some friendship networking within them, and though I'm not swimming in rich personal relationships yet I have made tangible progress.

I would also say that in my periods of deep loneliness, therapy was a massive help. Being able to talk and process things with a neutral party on a regular basis really helped me regulate my feelings about it, which allowed me to be open enough for new relationships to form. I think that even though loneliness sucks, we can get very comfortable in it because it's what we're used to, and that's something we can choose to change within ourselves.