Fighting :(

My boyfriend and I have been together for a year. We love each other very much. We spend a lot of time together and he treats me very well. But we have been constantly fighting for months now. It's about anything. From extreme things to small things. We keep trying to work things out, but honestly it's me. I get so upset about every little thing and I don't know why! Even after our fights I don't even remember why I was mad. I'm so sad and i really want to get past this and so does he, but I don't get why small things make me so upset. He has never done anything to hurt me or make me not trust him in the past so I have no reason to be so worried and upset all the time! I just want us to go back to how we use to be :( any advice?