Uh oh

EDIT: hello again, i believe this was a chemical or maybe indents im not sure. I got a line on a CB which came up.within the time frame (ill post in comments) but i have since had some dark red/brown and pink mucous discharge so im unsure whats going on now

Hi friends, ive just come off the contraception shot in november. I had unprotected sex on the 27th, took plan b the 28th of December and my period was due on the 2nd... is this a true positive? Or a side effect of the pill?