Never answered back should I care?????????????

Hi, okay. So this guy, we have been hooking up for the past month and a half. We used to date but broke up then decided to just hook up for a while. Friday night he came over and we had a great night. We laughed and had a lot of fun. So tuesday night i txted him around 11 and asked if he wanted to come over the next day and to just let me no. He never answered me. Also today he would have left to go out of town for about a week and a half so.... He always answeres me back so i dont understand?? He has unlimited txting and txts alot. so im not sure if this means anything. Should i just forget about him and not ever call him back, or when he gets home txt him something? what do u think. nice answers only thanks!!!!!!!!!!!!!!!!!!!!!!!!1