I am on birth control and occasionally "mess up" but it has never been an issue. I always have my period right on time for 4 days. I have not had sex since my last period but did right before it. This month I have messed up a little more on my birth control than usual. I got the cramps like I was getting my period but only had it for 1/2 day and it was extremely light. I am wondering if it was just due to the mess up on birth control or if there is a chance I am pregnant