Could I be pregnant?

My bf and I have been having unprotected sex for a while now and although we aren't necessarily trying to get pregnant the last few days have been quite strange. I've felt nausea all day long along with some vomiting at night. Along with with these symptoms I've also had cramping in my lower abdomen, sometimes a sharp pain but goes away after a couple seconds. My last period was a couple weeks ago but it was unusual being a couple days late and very light brown/pinkish spotting. I took two pregnacy tests then that came back negative. I'm unsure whether I should test again or wait until next week when I should have my period. Or if these symptoms are completely different from pregnancy. Please Help!