Why are my friends not talking to me?

i have never been very good at making friends. i was always in the in crowd but i never really have CLOSE friends. at the end of last school year, i finally found some real friends that i got close to. we hung out a lot and talked about personall stuff. they were really good to me. then during the summer it seems like they dont want to hang out or talk. theyll be busy one day so ill ask them to call me when their available to hang. a week will p and ill call again and be like hey wat happened? i feel like my friends have forgotten about me? help! wat do i do?