Side effects going off progesterone?

Momma of 4
I'm 12 weeks 3 days and stopped my progesterone supplement last night. I woke up in the night with terrible cramping so bad I couldn't sleep, and today it's continuing. I just had my nuchal translucency scan yesterday and baby was fine. I'm waiting for call back from my dr but was wondering if anyone else had side effects from stopping progesterone?