I don't know if this happened to someone before, but all this week I've been having cramps, and when I go to the restroom and pi I bleed, I'm suppost to have my period next week. And all of this started after I had sex with my boyfriend.

This is actually very common. I usually start cramping a week before my period. I don't think it has anything to do with sex with your boyfriend. I think that you are just starting your period earlier than normal. If the pain gets severe and your bleed heavy then I would see a doctor.

Did you figure out what it was?