Help! what could it be?

Okay so my bf and I had sex about a month or two ago, I'm not on any type of birth control. I've been having really bad sweet cravings and somewhat cramps but they don't feel like the cramps I get when I'm going to start my period. Today I went to the restroom and when I wiped there was blood. I don't think my bf came in me and I'm not supposed to start my period till the first of the month. So what could it be? Could I have started my period early?