My boyfriend and I have just started having sex, and he tends to go quite rough. a couple days ago (August 23rd) I started bleeding, and it hasn t stopped since. I wasn t too worried at first, but I m starting to get worried and would like to know if I should be? I ve been looking up whether or not sex can start your period, but seeing as mine isn t supposed to start until September 2nd I don t know if I believe that s what s happening, not to mention the flow of it all is nothing similar to my regular period.