Weird feeling in stomach

So my fiancé and I have been having sex lately and just since Friday night or earlier in the week, my stomachs been hurting/feeling weird. Don't know how to describe the feelings.  Last night my stomach started hurt too. Then today out of the blue it started hurting/feeling weird. Sometimes I'll feel nauseous that's how bad it is. Cant remember when these feelings started but could I be pregnant? Last month I got my period. I'm suppose to get my next one June 8th.