Severe abdominal pain, vomiting, dizziness, and lethargic and needing er care to get rehydrated and rid of pain during monthly cycle, what could it be?

Dysmenorrhea: You need to be checked out for ovarian cysts and a condition called endometriosis. We have wonderful treatment options available today, so you do not have to suffer. See your provider asap!

Slightly unusual: There is a possibility that you have pelvic endometriosis. Endometriosis can affect bowel function, and certainly causes severe menstrual pain. Ask your ob/gyn md to do a laparoscopy to look for endometriosis or take a medication called depo-lupron, which will stop your periods completely to see if your symptoms resolve while taking this drug.