What does this mean ?

I had unprotected sex July 30 which was the day after my period ended he didn't cum in me and I got my period every month afterwords but I was suppose to get my period nov 4 and never got it plus a lot has been going on with me lately I have very intense cramps and been having ups and downs with my bf the test was negative so can this be because of stress or am I pregnant ? Some one please help it would mean a lot to me