3 hour glucose test diet?

I failed my one hour glucose test and was told to avoid sugar and to eat a lot of carbs 3 days before I retake the 3 hour test. I normally have really low blood sugar and so far on the first day I’ve been feeling so light headed and yucky from skipping sugar. I can tell my blood sugar feels too low. What diet were you told to eat before your 3 hour glucose test? Did you pass or fail?