Zippy man. I can totally relate to what you are going through. I had a sh1tty high school too. I followed this one girl for 2 years STRAIGHT. i was pretty much her *****. Everyone thought we were going out at one point, but at the end of the day, she was just using me(for my car). Of course I thought about her all the time. Stalked her house sometimes to see that she wasn't hanging out with other guys.
I had it pretty bad man. Introverted, a loner, short, skinny, no hobbies, etc. It all broke down when one of my closest friends ASKED her to winter formal and she said yes. She said no to me for Junior Prom. On top of that, my parents booked plane tickets to asia and I had to leave during winter break. I was going out of the country in one week. The girl I loved for 2-3 years just said yes to one of my pals on a DATE(something I dreamed about everyday/while Ill be out of the country). I literally wanted to kill myself. I quit Cross Country(my only outlet from my depression at that point). Attempted suicides in my car. I never talked out to anyone. Kept everything inside. I DIED inside.
I'm telling you man. You GOT to get out of the mindset. What helped me out of it? Going to college. A fresh new start. I can start all over again!!! The next thing that helped me out was my outlet. I went to the Gym like mad. After running into this site, my life really got better. Sure Im still a virgin, but I had one f-close, and two gfs since then. You can do it man.