How to get over someone very special to you?

About three months ago, my ex-girlfriend had left me out of the blue for a 28 year old guy. Her and I are 19 years old. So, disregarding the fact of how I feel about Her new boyfriend's age, the fact is she cheated on me with him for about two months before she decided it was best to get rid of me.
She is beautiful... Truly gorgeous, so I should have known I wouldn't have been able to keep her for long, but I was convinced it would never end. At least, that's what she made it seem like. She never did give me a reason for leaving, other than she felt like we were meant to be friends, or everything happens for a reason, etc... When really, this is what she meant I'm assuming, "This guy's **** feels so much better than anything you could say, do to, or for me, so bye." She always promised even if we broke up she would never stop being my friend. She knew how important that was to me too. I haven't heard a word from her since she broke up with me a few days before Valentines' Day.
I guess you could say I wasn't her type. I'm pretty introverted and just as sexually inept as I am socially. She wanted someone to please her not only mentally, but physically as well, and I could never fulfill that for her although I would have risked death to do so. She got tired of being with a loser and wanted someone better, it's that simple. The guy she's with now is everything she could want and I feel so inferior.
It was the first time a girl ever stayed longer than a couple of weeks. I have always been left for someone else. It's always for the same reason too, "I think we should just be friends." You know what I think? I think every guy that has stolen a girl from me is real lucky that these girls don't tell me where to find them, because I would gladly kick the teeth down every single one of their throats. I have come to the conclusion that it would be for the best to never have a relationship past friendship with a girl. The dating world is a competition, and I'm just not fit for it. I could never make a girl as happy as they could make me. There will never be a girl that will stay because there is always going to be someone that can make her happier. I just want to lay in bed. I'm absolutely obsessed with this girl. She is in my head constantly and the urge to go find and severely kick the hell out of this 28 year old honor-less tool grows with each passing day. I hate her, and him. Yet, it's usually the only thing that I think about. I need help. The psychologist helps about as much as a placebo does... not at all. Idk what to do. I quit my job, I don't go to school. I have given up. I no longer enjoy living. I just want to be happy, but it's impossible. When the desire to live is gone, what is the point of living, ya know? Advice, help, support, idk. I just need help.e

This sounds like clinical depression. It is too much for just a regular romantic break-up or even two in a row.

Whom are you seeing for treating the depression and what is being done? The psychologist is like a placebo - what else have you tried?

With girlfriends, you will eventually find your luck. But the current priority is to go to work and/or school.

Hello Mapexx93!
I am pretty sure you will find many other love interests in your lifetime!! At 19, i thought i knew true love, and was devastated when it ended, but that feeling passes!!
Get busy with your life. isolating is only making it worse. Get a job, go to school, and meet people. Find a hobby. Get counseling.
When someone leaves a relationship, it's their free choice, so knocking teeth out may sound like a good idea, but in reality, it's not!! The girl is probably just not mature enough to know what she wants yet. DON'T TAKE THINGS PERSONALLY. It's usually not about you, most people are selfish and it's all about them.
As long as you are a good guy who treats people the way you want to be treated, and do no harm to others, i believe you will meet someone. Give it time, and remember beauty is only skin deep. There are many young, smart, caring ladies out there!
sans