I had protected sex on 7/27 and 7/28 and its now 7/31 and im having cramps and tender breast, my period is supposed to be coming, can I be pregnant.?

Get EC. If you don't want to become pregnant, get some emergency contraception (EC) from the pharmacy, drugstore, or grocery store. You can take it up to 5 days after unprotected sex. It's too soon to tell if you're pregnant, but if you are, the EC won't affect it.