Hi there! Don't stress! I took my GRE August 15th last year, was not happy with my performance, and took it again September 19th. I called the schools I was applying to and explained the situation. I put down my quant/qual scores on the VMCAS application and they were fine to receive my writing score a bit after the VMCAS deadline. Just check with the schools you're applying to.
So, you will have all of your scores by the VMCAS deadline if you just take the test on August 17th - and my guess is you'll rock it so you won't even have to worry about another test date
😉 Best of luck!!