Should I test?

So my boyfriend and I had sex. He didn't come in me but we definitely were not as careful as we should have been. I had my period. It was heavy like usual but at the end it would stop and start spotting for a few days which was weird. At that point I thought I was good but this entire week I have felt pretty nauseated and tired. I blew it off for the first few days but feeling bad this long is starting to freak me out. Is there a big enough chance that I could be pregnant? Should I test or just wait to see if I get my period next month?