A need for attention is getting in the way of my social life

Hi everyone,

First of all, before I even begin, I'd like to apologize for two things: 1. Sorry if this is in the wrong sub-forum. I wasn't sure if it would fit better in DPD or NOS, and 2. Sorry for the long post, but I feel it's a lot to vent if I want to get rid of this, and I want to try and provide as much detail as I can to give a good idea of what's going on.

Anyway, it's my first time here, so for a quick introductory background, I'm a 20 year old guy who's enrolled in a Psychology course (go figure) at University. I've been going through a lot of ups and downs since I was 14, a lot of antisocial issues and mood swings, but I've seemed to settle down quite well in the past 5 years and brought out the funny, charismatic and caring guy I was meant to be. However, there's a few terrible qualities that I desperately have to get rid of, and it's why I've resorted to posting here; as they're starting to get in the way of my social life and my relationships with others.

I'm a massive attention seeker. That's it. I'd go through all my Facebook posts from like, 2009, and noticed how often I'd post 2 statuses a day, and it only clicked now that it was just for attention. What's funny as that I tend to seek attention very passively (well I guess attention seeking is kind of a passive thing anywya), but I'd go around posting something negative like a sad song or a plain status to vent my frustration over the girl who isn't talking to me. It's happening again now, except with no Facebook posts, of course.
I'll give a short example of how this attention craving is clouding my view on this particular person: I'm close friends with someone I've almost developed a crush on, but man, what I'd do to get a simple 'hi' on her end for change. I get so irritated when I see her being friendly with other guys, to the point where my overthinking kicks in and negative/pessimistic thoughts just start flowing out: She's acting all friendly with him and not me? Fine, I won't say a word to her today then (lol jk, I end up caving after a few hours). You know what the best part is though? She DOES talk to me, but at this point, I've thrown the whole thing out of whack that I draw stupidly pessimistic assumptions from the way she talks to other people even judging by what tone or smilies she uses. It's that bad.

My point is; my overthinking and attention seeking from this person are really affecting my mood and I just want it to stop. I'm usually all bark and no bite, so most "Just go out there and do something about it" advice will have to be pretty motivational - I'm not shooting it down of course, I'm all ears for anything - but I'll do my best with whatever I can.

TL;DR: Passive attention seeking for one person and overthinking is a b*tch, even when they give you a fair amount of attention. I draw negative assumptions like "She likes him more than me" or "She thinks I'm annoying" when chances are it's probably not even true.

Yeah, it's a little clear I'm pretty sensitive for a guy, but that's just being human for you I guess. If anyone read the whole thing, thanks a lot, and any and all comments/advice is totally welcome.

Have a nice day and an awesome Christmas!