my boyfriend and i had unprotected sex, but he's almost positive he never came in me, my period following the sex was 3 days late. however, today i got my period. i've felt like i need to throw up and i've had on and off cramps all day. could i be pregnant? also i've been hearing that you can still have your period during pregnancy or that i may just be spotting due to implantation but i've had a lot of blood, much more than spotting.