>>1
Finding something else to like and do it with all your heart. Obsess over it. Then your other feelings will be buffered and eventually boil down. When you are cured, you'll still have a hobby.

Ie, pick up an instrument and learn to play it really good, a sport, writing, drawing, painting. Actually, a hobby that allows you to express yourself is the best.

You might want either to practice that alone (if you think you'd rather take some time for yourself so others don't hinder your progress by talking with you about subjects that might bring the girl up), or in a group if you feel that it would help you not developping a social anxiety. Good luck!