Could I be pregnant?

Last month, July 7th to be exact, my boyfriend and I had anal sex due to the fact that I was on my period. After he finished I attempted to clean myself a bit with a towel and quickly drove home. When I got home to shower I noticed some cum had dripped down to my vaginal canal and was a bit in there, I quickly removed my tampon and showered. The next day I took the morning after pill, now it's August 11th and today I am 6 days late. (My last period started July 5th) any thoughts?