Need Advice for Rescheduling my GRE Exam

Hi Everyone!
I hope you are doing well. I’ve my exam scheduled for the 11th of July but I’m still unable to do well in Greg quizzes. I’ve covered all the prepswift videos and did some reading as well. What do you guys suggest?
I already scheduled this once but now I still thing my prep is not up to mark.

What do “Greg quizzes” refer to? Which ones exactly?