Confused and Scared

Ok so my BF and I had sex last Sunday night he pulled out before anything could happen, but I'm still worried. My chance of pregnancy that day was very very small. My period is suppose to come this Tuesday(May 10th) and I've had gas and cramps. Today it looks like I either started spotting or maybe my period came early. I just can't tell if these signs are meaning my period's coming or if I could possibly be pregnant. I've been stressed about it because at the beginning of the week I felt sick to my stomach. Any insight would help!