Ovulation question, please advice...

Erica Grace • Originally from South America, but live in the state`s for the last 23 years
I had mariena for 3 1/2 years, took it out on Sep 3, AF arrived the 6th and it lasted 6 days. My days of O are 15-21, and have been baby dancing regularly. Last night I was so crampy that it woke me up at 3 am and I had and awful rest of the night. Still cramps when I got up in the morning and just not feeling right. Is this normal??? I''ve had mariena for so long I don't even remember what it feels like to O. Please advice, I'm kind of freaking myself out...Thank you and baby dust for all