Help!?

Okay, 2 days ago i started getting really bad cramps. Like, crazy bad. It started after i ate little Caesars pizza. They were so bad i left my basement of friends & went to bed. Yesterday i woke up & still felt them a little but not as bad untill further through out the day. Then they got bad again. Today i was sitting on the front porch & they started hurting so so bad again. Ive pooped since than and it was black. Im 17w2 days pregnant what do i do?!