What Causes Irregular Periods With Dark Brown Discharge? Suggest Treatments

For two months I have been having a cycle approximately every other week lasting 7 to 10 days so far I have had 5 . This time instead of blood it is a dark brown discharge very sandy or grainy as well I have P.O.P. so I have very painful intercourse at times so bad I can t move ovarian cysts and a IUD sometimes for no reason I will have extreme internal and external spasms that effect both vaginal and anal areas what could this be and what should I do