Amanda,
Everything you are feeling sounds like a pregnancy to me, and even more if u got off of your birth control and had unprotected sex during that week, I think what you should do right now first of all is take a pregnancy test to know if you are or not pregnant. And as far as I know, taking your birth control back (in case u got pregnant from that week) shouldn’t terminate your pregnancy but in some cases it can cause an indirect negative effect on the baby. Those cramps u say can mean a lot of things so you should have a talk about this with a doctor. Hope this helps. Best wishes!