When should you go to a doctor for menstrual cramps?

I'm 15 and every month a day before and a couple days into my period, my cramps are excruciating. I can't do anything but lay in bed curled up. It's like someone is stabbing be "down there" and in the back. Pain killers don't help. Should I go to the doctor for this? About a month ago I found I have a one inch cyst on my ovary, if that helpful to know. Thank you for any answers.