Hey man I'm right in your shoes. I just got dumped by my first girlfriend of 8 months last Friday. It's the hardest thing I've ever been through, because she wasn't only my girlfriend, she was also my best friend. And now that's all gone. She was the one that I went to with all my problems. Now I'm learning that I need to be dependant on God with my sorrows, not girls or family members.
My advice to you is to read your Bible for at least 30 minutes a day and pray for a good 15 minutes a day. Breaking up causes extreme feelings of loneliness, worthlessness, and depression (I've felt it all, as I'm sure you have as well). When you get right with God, all of those feelings fade away. I've gotten so much closer to God and this is your opportunity to as well.
In your time of singleness, become who you are really meant to be. When you were dating your girlfriend, your likes and interests conformed to hers, so basically you two were starting to become one in thought. When you guys break up, you become independent again. Become everything that (if you were a girl) you would want to be as a husband in Christ. Get re-instated in your hobbies that you took part of before you were dating. For me, my biggest hobby is road cycling. Once I started dating, I was in a road cycling club that rode 20-40 miles in the country. I loved it! I stopped doing that once I started dating, but now that I am single again I am going to sign up for the club.
Lean on God. He's the only thing that you should be dependent on.
Love ya as a brother in Christ,
Will