Pregnant??

My boyfriend and I were messing around and while we didn't have sex, his parts touched mine. I don't remember if he came before or after that. At the time I was 2 days away from getting my period and got it on time. My cycle is generally 29 days. I'm now 2 weeks past that event and my stomach is hurting, I'm getting head aches, nausea, constipation, and slight cramping. I took a pregnancy test today and it said nagative. Could I be pregnant or just freaking out?