What can i do to not feel insecure in relationships?

I have been divorced for years and have tried dating... it hasn't worked very well... nothing bad but things haven't worked out. So I met someone that I am very attracted to and he is really excited about me. He has talked about the future in only 2 weeks of dating which instead of scaring me it gets me really excited because he is (I feel) the person I 've been looking for. But I feel myself feeling very scared and insecure and I am afraid i will run him away. When a day goes by and he doesn't contact me I am assuming he is getting cold from me... I try not to bug him much but I feel myself getting needy and wondering in my mind if he is talking to someone else. How can I control my feelings, take it easy and slow? I wake up terribly sad, really sad if I didn't talk to him the day before. I know most of people reading this will think I am annoying but I am trying not to be. Please help me.