I really hope things start looking up for you and getting better for you. I know sometimes the teenage years can be hard. Especially if you have overbearing and strict parents, you are kept apart from your friends, maybe if your parents come from a different culture and cant relate to you, if you come from a family that is overly educated and you dont feel like you fit in with them, etc. I know b/c I have been thru all that when I was your age. And I definitely can sympathize.
Keep in mind you are not the only one going thru all this. You said you are 16 and you have had only 1 gf. Thats not bad at all. When I was 16, I didnt have any bfs (I'm a girl). Not until I was in my early 20's. You are only 16 and you will meet other girls. By the time you are older you will find a girl whose right for you, I guarantee it. At this age, try to find out what you want in a girl. The teen years are great for figuring out what you want in a partner. By the time you are older you can settle down. I'm sorry your relationship with this girl didnt work out, but if she doesnt want a guy who treats her well, well screw her. She isnt worth your time. She will probably meet guys who treat her like sh*t and then once she's older she'll regret how badly she f*cked up the relationship with you. I know b/c my gfs regret their past mistakes with nice guys.
My advice is to see a psychologist at your school. They are free and confidential. Also get involved in an activity/new hobby or sport. THere you will meet like minded ppl.
Hope it helps and good luck.