Waiting period between 1 hour glucose test fail and 3 hour test?

I took the 1 hour test yesterday (at 28+2) and failed with a 178, and my doctor recommended waiting 7-10 days before doing the 3 hour test to give my body a break. I scheduled the appointment for 10 days from now just to coincide with my next OB appointment, at which point I will be 29+6. Is there any harm in waiting so long in between these appointments? Should I avoid sugar and carbs until then just in case?