Cycle started 1/20/17. Had unprotected sex 1/27/17. Took Plan B One Step 1/28/17. Had no symptoms initially. But 5 days later, I started to have headaches, light nosebleeds, heartburn, gas, tender breasts. Where I'm growing extra concerned is that on 2/12/17(day 24 of cycle) I experienced very light spotting. It was pink in color and only was there when I wiped twice. I have four children, and if I did not take this Plan B, then I would be certain that I am pregnant, but because I did take the pill I am not so sure. Does what I described sound like implantation spotting, or Plan b spotting?