Okay, I have never had regular periods. I never know when I m going to get one, and I go months without them. I ve been having unprotected sex and the other day I bled very lightly and only when I wiped. It was light pink, I thought I was getting my period throughout the day it went from light pink to a dark brown and I only bled for one day. I read that this could be from implantation bleeding. I ve been very nauseous and unable to eat for almost a week. I ve been having unprotected sex for almost a year and never gotten pregnant. Could I possibly be pregnant?