4cm ovarian cyst. Several sudden sharp pains over the last 2 days and clear fluid leaking from vagina...Could it have ruptured? In a lot of pain

It is very possible. Would recommend seeing your ob/gyn as soon as possible or reporting to er for further workup to be safe. Best of luck and hope you feel better soon!
Yes could have. Please see your gyn or go to the er an ultrasound and blood work needs to be done.