You’ve figured out something important already. The problem isn’t in the relationship. It’s in yourself. Your girlfriend can’t make you be happy. A relationship is happy when both people bring a strong sense of self to it.
I agree that you need some help dealing with whatever is causing your tendency to sink into depression whenever things are going well. Please consider talking with your parents or a school counselor or another adult you trust about seeing a therapist to sort this out. Too shy to do that? A place to start might be the Boys Town National Hotline at 1-800-448-3000. Counselors are there 24/7 to talk to young people who are struggling with all kinds of personal problems. If you’d like to find out more about Boys Town before you call, go to their website at www.boystown.org
You made an important first step toward taking care of yourself by writing to us at Psych Central. I very much hope you will take the next steps so you can have happiness in your life.
I wish you well.