I've been having suicidal thoughts recently too, but right now, I think I'm on the up swing, or at least almost up swing.. so I wanted to share similar things i've experienced with you so you don't feel so alone.
I can totally relate to wanting a bf/gf so bad in HS...every year, i thought that'd be the year. I just kept getting disappointed though. Funny enough, when I decided that I didn't care if I got one anymore, was the year that I actually got one. (He just wanted to get in my pants though, so it was short lived and made me have low expectations for future dating.)
I also had a really small circle and bounced between groups, but I thought that made me cooler, more well-rounded, because I could observe different kinds of people/groups, even though I didn't know everyone in those groups either, and yeah, the people who didn't know me didn't care to get to know me more. But, I dismissed that to people usually being self-absorbed). It did get lonely sometimes though and I envied tight-knit cliques, where people didn't have to bounce between groups. A couple years after high school, one of my friends from one of the groups I bounced into had died. That friend was one of few who I was somewhat close with and, even though I had considered suicide years before, I never thought I could be depressed until their death. I'm still recovering.
You say you want to have more friends, but having more friends doesn't necessarily mean you'll be happier. My advice regarding your desire to expand your circle is to first focus on yourself. To attract a great group of people, you have to first be someone that they would want to be friends with. Be a good friend to yourself. You can remind yourself of what a good person you are by listing a number of positive things about yourself and looking over them when you need to.
You can also find out what you like/want to do and search for groups on meetup.com that are related. Take yourself to a meetup, even if it feels like a lot of work and allow yourself to be happy. I drag myself to the same meetup every time they have a meeting, which is once a month or once every few months even though it requires driving all the way downtown from the suburbs and it's after a long day of work.. I always never want to go until the last minute and get there late but I always enjoy it. I mostly I meet cool people and have good conversations. I also used to care more about how I acted in them and whether i would actually become friends with the person I was talking to, being stiff and stuff..maybe social anxiety?, but I realized all of that didn't help. So the last time I went, I was pretty lose and had a lot of fun not giving a damn about societal norms AND I was sober! I was practically back to my 'old self' and I barely recognized me.
Anyway, the point here is that it does get better, and it isn't going to be overnight, but I wish you luck. You've made a lot of progress already, getting through past suicidal-ness and depression. You're also dealing with it a lot better (before, you turned to drugs which is a short-tem solution as you yourself pointed out, and now you've turned to reddit and making friends, which is much more sustainable and is a very smart idea). You're a smart guy, OP. :) You're also strong to have gone through what you've gone through and still fighting the good fight. For what it's worth, I truly believe in you. Good luck, dude!