How do I get over being quiet and nervous around everyone? ?

I'm 16 and a junior in high school. All throughout high school I've been called the quiet girl & asked by almost everyone why I'm so quiet. I've been picked on alittle from being so shy and quiet. Even my teachers treat me differently because I'm so quiet. They look at me like I have four heads and once one of my teachers told me I'm too quiet and I need to talk more to get a better grade in his class. I hate this so much. The more people tell me in quiet the more I feel crappy and make me feel nobody likes me because everyone thinks I'm weird. My freshman year this girl told the teacher infront of my face she didn't want to be my partner for a project because I don't talk and I'm boring. Sometimes i cry myself to sleep because I hate my life because I can't just be normal. I have no idea why I'm so quiet and have a hard time making conversations without being so nervous. Me having not alotta friends doesn't help the situation either. I used to have a lot of friends but now since I'm in high school we just don't talk anymore. I don't hang out with anyone anymore either and I feel like a loner. I already talk to a counselor about my depression and stuff but she doesn't help at all. Alot of guys try to talk to me because alot say I'm really pretty but when they find out I'm so quiet and don't know how to star a conversation they don't talk to me anymore. :( it's hard for me to be in a relationship. I'm not too young to be in a relationship. I've never been in a relationship and i wanna find that someone who will make me happy. :( I'm so depressed over this. How can I stop feeling this way and be more open and less nervous. I wanna change my life. :(