I need advice.......

My boyfriend and I who are both 15 and been dating for a year, have a pretty rocky relationship that has a lot to do with my behavior. I’m extremely clingy and obsessive and bipolar and I expect everything to be perfect and everyhing to always go back to the way it used to be. I can notice it stresses him out and I bothers him and he becomes more distant and he’ll do things like give me the cheek and barely text me anymore andI feel horrible. He loves me and tries to be there for him but I feel like I’m not doing the best. How can I stop and be a better girlfriend??? I’ve never acted like this before with anyone and it’s very shocking I want to be a good girlfriend and I want us to be happy. Someone please give advice.