Cramping in Abdomen/ Pelvic area

Mandy
Hi all- I am TTC and just went off birth control last month. AF is due 10/9. Last night I had horrible cramping in my lower abdomen and pelvic area. Almost so bad that I wanted to go to the ER. I have ulcerative colitis, interstitial cystitis but this didn't feel like either of those. I have had ovarian cysts before too but nothing this painful. 
Any ideas?? We did TTC on a peak day during ovulation on 9/23. But only once so far.