Concerned

Well I never have had anything to put on here but now I do. My boyfriend and I have been together for almost 3 years now, we are sexually active, I am on the pill and we don't wear condoms but he pulls out every time, never has finished inside me. But I only have my period 4 times a year, once every 3 months so sometimes I get a little worried. The past few days I've been feeling more hungry, more moody and tired. I have been under some stress with my classes and working two jobs so I'm not really sure. I haven't felt nauseous but I haven't exactly felt right either. My boobs aren't tender so that's a good sign. Just curious if anyone thinks I could be pregnant? I don't really think I am but I'm not sure why my body is acting weird and why I'm feeling weird. Any comments would be great. ?