I'm 27 An Iv Been Cramping Really Bad Sometimes So

I'm 27 an iv been cramping really bad sometimes so bad that I cant move no matter if standing or sitting down an sharp pain in my pelvis area. iv not had a period in a long time like over four months all that happens is I spot sometimes light to really really dark blood an sometimes clots with it. I know I'm not pregnant iv also have had weight loss sometimes moody an sometimes more than less pain with sex so bad have to stop sometimes . should I have this checked out an what do you think it could be