I always get obsessed if I have a chance with a girl, or If a have a girlfriend..
I'm constantly working out, and pursuing my hobbies, but If I get a serious chance with a girl (for e.g. this time I've kissed a girl in a party, but I really shouldnt care about it) It's easily ruined. So how can I prioritize my tasks over girls and get myself to not to think about them so often?
The reason you feel like you're obsessing too much about girls is because you're putting too much weight into the signs you're reading. For instance, kissing a girl in a party is not that strong of a sign you have a serious chance with her. Especially if alcohol was involved. It might help you to look for multiple signs before you start expending too much mental energy on any individual girl.