What Causes Burning Sensation And Blood While Urinating?

I had sex with my boyfriend about two weeks ago. I am not supposed to be on my period until around the 26th of this month. My boyfriend came inside of me and didnt tell me until the next day and so i took plan b in the evening of the day after sex. Yesterday I noticed that there was light pink dots when i wiped. Today when i went to the bathroom it burned and there were dark red dots on the tissue. Am i pregnant?