Why do i have severly violent dreams before and during the time of the month?

i have noticed that before and during my period i been having violent dreams and idk where they come from and this has been happening like a couple of months. the last dream i had before my period i was walking and these boys was waving at me and flirting with me then they was walking slightly ahead of me talking then this guy gets out the car and pulls out a long barreled shot gun and shoots them all down except one in cold blood the one that was in front of me tried to run but he was gunned down as well and the guy tried to come after me and the one before that someone's head was getting chopped off what is wrong with me?