am I jumping to conclusions

I've been having unprotected sex with my boyfriend for a while now. I am on bc but I've been drinking it a couple of hours late. Since last week Thursday I've been nauseous, and I just started getting lightheaded/dizzy. Then I started to get some cramps. ( very few) however the nausea never went away. I sometimes struggle eating cause after a couple of bites my nausea gets worst. could I be pregnant? Or is it just my period?