Late period and had anal sex could I be pregnant?

[MCGIRL838]

I had anal sex on March 5th and my period was supposed to come on March 26th currently I'm 11 days late for my period. My last period was February 26th, could I be pregnant? I already took a pregnancy test and it was negative and that was 9 days after my period. Sometimes he slipped out and it may have touched my vagina but we never engaged in vaginal sex. I have been 9 to 10 days late after my period before but never this long. I also took a trip to Washington DC on March 30th and we had many sleep deprived nights, I didnt know if this could be why or there is something else wrong with me.