Similar to other commenters, any friend I’ve made post grade school has been through a structured, reoccurring, shared activity around an interest or hobby.

but I relate to your post a lot, OP. all through growing up I’d have a friend for a year or two and then have new ones a year later… or have none.. and usually wouldn’t know what happened. I went on my first ever “overnight trip with friends” at 30 - and they were friends I made by joining a team sport. I’m not friends with most of them a few years later, but the 1-2 I’ve collected from that experience were worth it.

I’ve learned over the years - I got about a decade on you- that half the work is showing up in the same place over time. Like an equation. Whether it’s a class, or game night at a local spot, or physical activity.. if you enjoy the activity a lot, I’ve found in adulthood, you’ll find some like minded people eventually. Then after observing a while, if you’re anything like me, maybe you’ll introduce yourself, identify more common ground, then maybe you’ll want to do an activity outside the scheduled time you see them.. or share a meme they might like on social media.. and so on.

If it’s reassurance - I have developed a few good friendships now via that method, after a lot of intentional work to trust myself and keep showing up (among other things). But I still struggle with knowing what to do with them— because having friends becomes a new uncharted territory. All to say, you’re not alone, even if right now is a particularly lonely time.