Is it just normal discharge?

Latoya • Excited and nervous pg with my son and a mother of an 8 year old daughter
Ok so I'm 21 weeks tomorrow. I was sitting on my bed and felt a huge gush of what I think may just be discharge. I rushed to the restroom my panties were soaked and it was running down my leg...its mostly clear with a small tent of white. Cleaned myself up but now my stomach is having light cramps... Has anyone had this happen or do I need to call my Dr?