Late Period, now spotting?

I hadn't had a period for about 2 months but hadn't been sexually active and not being on birth control it was a normal thing, so I wasn't concerned. I started dating someone a month and a half ago and may have made a mistake and not used a condom one night. We went and got the Plan B morning after pill just to be safe. About a week later I started my period but it was unusually light. After a week I thought it was done, which was also weird because my periods usually only last about 4 days. Now I'm still spotting but it's brown and a weird consistency. It's been 2 weeks since my period started and the spotting for a week. Does anyone have any helpful insight on what could be going on? I've never had this happen before?