Why does my boyfriend not wanna hang out?

I worked all weekend so we barely got to even speak. I come home from work early and invite him over to eat pizza with me but he says he is full. But I still want to see him so I let him know that he is still invited over. He ignores the invitation and asks if I can finish a box of pizza by myself, and from there forth the topic has changed. It feels very much like he does not want to see me. And thats how I always feel when I ask him to hang out. Because a lot of the time he says no.