I am experiencing bad cramps after intercourse and I don't know what I should do? This has never occurred before..

Cramps. This could be a few things. First, check a pregnancy test as it is common to cramp after sex for a couple days. Second you might want to try taking some ibuprofen and advil 30 minutes or so before sex to see if its uterine cramps. Lastly if this is new in onset, its probably time to see a gynecologist to rule out early endometriosis and infection.
This needs to be. evaluated by your Gynecologist! Donty ignore it! Hope this helps! Dr Z.