I still remember what it was like to 'love' someone who did not love me back. Jealousy, paranoia, unreasonable anger, depression...and if they ever deign to glance in your direction its like the sun just burst over the horizon. I went through that at least a dozen times in high school- and never had a single gf until I was a senior. You see, I was but 5'2" until I grew to 5'10" in my senior year and all the girls who used to look me in the eye (or down as the case was, I did like statuesque women) could no longer do so, and they began to take me more seriously. So I had two gf's in my senior year, and ended up taking a dead ringer of my 2nd gf to the prom...she was prettier too, but I did not enjoy that evening.
Pretty much all of what you have already read from the others is tried and true wisdom...look not at our ages and scoff, because we have all been there, to varying degrees, and apparently remember quite a bit of what it was like to be young, passionate and foolish in 'love'. I put it in single quotes because I can tell you- I hadn't had a fucking clue what it really meant.
I got married early on too, when I was 20, to a 23 year old woman that I'd met thru a distant relative who she'd been dating off and on for several years. We fell hard; mostly because it was 'forbidden', you know? It was almost too easy, I should've known better you could say. It was all lust, fully charged- like lightning is attracted to a lightning rod, so we were.
I used to wonder at myself because I have always been able to 'turn it off', emotions I mean...which I now understand only meant that I wasn't truly in love. I married again, to a most wonderful woman who had the heart and decency to show me what love really meant...up until I met her, I only had what you could call a textbook understanding of the mechanics...and was totally lost as to how I would ever get to that point. I think of her all the time, wonder how she is, what can I do to make her smile, make her happy? I realize now, for me, that true love could only come when I was willing to put her before me- to consider her feelings, her thoughts before my own; I had never done that before in my entire life. Never. And yet now, it is as natural as breathing. Don't get me wrong, she's a woman so there's always going to be something that strikes you as odd, or what have you, but you'll find that it really doesn't matter in the grand scheme, because you'll find, as I did, that you're so much happier than you've ever been and you can honestly envision the two of you living your lives together, and she shares that vision wholeheartedly. I hope you find that, I hope everyone finds that for themselves one day.
I spent a lot of my adolescent and teen years wondering who I would end up with, had all these lists and dreams and the like...I remember the angst, wondering if this one or that one liked you. I never went to my junior prom because I couldn't BUY a date. Seriously. I had all these female friends who wouldn't go, because we were just friends. I later learned it would've been somewhat taboo to show up with a black guy (predominantly white school)...ah, that's life, my friend. Disappointment is part and parcel of the growing up experience...you never get used to it, you never really learn to accept it- but if you're smart, you learn to rise above and beyond it.
This ex of yours wields a certain amount of power over you that she DOES NOT DESERVE. No woman does, unless she is as much yours as you are hers...and you can only learn that over time. I don't mean to keep on about age, but by the time I hit 30, I'd been with a lot of women, of all different types, backgrounds, philosophies and races. I found distinct similarities that simply confounded me- couldn't stand some of it so when I got fed up, I'd walk. I was a serial monogamist...I'd go from one to the other once boredom set in. I kept those relationships to less than 6 months...about all the time it took for them to piss me off. I also discovered that women are women, just like men are men...the key is to find the one who is right for you, and there is one out there. You may need to be patient.
I sometimes wonder, if I'd met my current wife 20 years ago, if she would've considered me at all...I was a different person, not altogether bad, but definitely more self-centered and less amenable to the desires and needs of others, I was pretty selfish. Getting married the first time forced me to grow up because all of a sudden I had this 2 year old babygirl and a wife, and soon after, another child on the way...a lot to deal with at 20 when you're hardly an adult yourself. I've always had to do my lessons at the school of hard knocks because I rarely listened to the advice of my elders (and usually betters)- figuring with typical adolescent arrogance that I knew better than all of them. I did not. Not at all. Of course, my first marriage failed but it taught me a lot about myself, about relationships and how such things should never be taken lightly, but should not cast a dark pall over every other aspect of your life simply because it did not turn out as you wanted it to. This happens, in all aspects of life...prove yourself resilient and able to adapt and you will succeed- it is our sincere hope that you are able to get out of your funk and back into the swing of life...but only you will determine when and how that happens. Keep your head up, my young friend- your whole life is ahead of you, the choices you make will resonate throughout that life so choose wisely when you can, and it doesn't hurt to have a little faith...in yourself as well as others. Be well.
I get the heartache, I get the desire for revenge- I hope that you manage to get past this and move on because I promise you, this time next year, it'll be nothing but a distant memory- provided you're involved w/someone else. Nothing helps you get over the last girl like a new girl. Sounds crass, but it is undeniably true.