Do you think in pregnant?

I have been have with my boyfriend for a bout 5 months now. We have never had unprotected . We always use a condom n when we are done the *** is always in side the condom. My last period began between march12-16 I don't remember the exact date n it lasted for bout a week. Lately I have been feeling a bit nausea! I have always had a problem that when ever I eat I feel like iwant to throw up but this time I just I might be paranoid. I have also been gettin a bit of sharp paints in my stomach. My friend suggested that it might be a stomach virus. What do u think. So far I have never in my life missed a period n I expect my next one round april 15 or so!! Help me I'm a bit worried!