Hi Stacy, welcome to Health care magic forum.
As you describe there is abdominal pain
Spotting in between the periods,
Regular periods are light and brown in color.
Your problem appears to be due to be duet to some problem of genito urinary system
It may be urinary tract infection
, pelvic inflamatory disease, stones in the urinary system, or poly cystic ovarian syndrome etc.
I advise you to consult a gynecologist for diagnosis and treatment. You may need to have M.R.I. besides other routine tests for confirmation.
Wishing for a quick and complete recovery, and thanks for calling.