keep having dreams about my gf doing horrible things

For the past few weeks, almost every dream i can remember has my girlfriend as a main part of the dream. Usually this isn't bad, just dreams that happen to have her in it, like one where i visited a mansion and she was there with me. But for the past week or so all my dreams have been about her doing something out of character for her. Like her yelling about how awful I am. I don't know why my dreams suddenly started being negative, nothing bad happened in the relationship or anything like that. Thoughts or any ideas as to why this could be?