Depressed....?

Well, I have been depressed since I've broken up with my girlfriend of 5 years. I broke up with her on the end of summer in 2007 and I feel worthless. She was my shadow; everywhere i went she would follow. We were unbelieveibly close to eachother. We were attached in every way imaginable. These were the best years of my life, and now I feel so empty. I devoted my life to her and I've been thinking about suicide. She broke up with me because she called me a mean name (she was just playing), and my sensitive a** said i was going to kill her and she took me seriously and now everything is over. I am thinking about getting a new girlfriend, but I don't know how to. I don't know if people want to go out with me, if anyone likes me. I like this one girl in my homeroom cl. There is nothing wrong with me, I guess I'm attactive, everyone says I'm cute. But I don't know how to approach a girl to ask her out. I am painfuly shy and terribly sensitive. Can someone tell me how i can overcome this