On Monday night, my boyfriend and I had sex. However, the condom had slipped off BEFORE he even was near ejaculation. He did not ejaculate at that time. However, I was nervous so the next day which was Tuesday, I took a Plan B pill. Later on Tuesday night I had a bad headache and felt really tired. Today is now Sunday, and I noticed that there is a light-brown,reddish brown, coppery color in my panties. It's not a heavy flow like my period, it doesn't even look like my period it looks like the end results of last months period. My period usually comes around the 28th of the month. Why is this happening? Is this normal? Should I be concerned? Is this my period coming early or can I expect it in two weeks when it is do? Please answer.