Symptoms ????

My period started the day before Thanksgiving and has not stopped yet. It slowed down after about 7 days and then got to where it was almost stopped and then started again, deep red blood for about a week and a half, then in Dec around the 27 I started bleeding bad again and passed a big clots, also passed a few smaller clots before that, now it has slowed almost to a stop, seems that in the am when I get up I have been bleeding and then just a few spurts thruout the day and by night has stopped. I also checked the other day and the strings for my IUD are not there????
  What are the symptoms for ovarian cancer.
          Thank You