I had a number similar to yours for my 1 hour test. My OB had me do carbo loading before my 3 hour test and I passed it with flying colors. I didn't do anything special with my eating up until I did the carbo loading the day before or maybe 2 days before? Can't remember now. It was also the holidays and my baby shower in my hometown was right around that time, so I definitely had some sweets.
I will also pass along some anecdotal info on the size of your baby. My baby was always measuring on the bigger side (80 some odd percentile) throughout my pregnancy. I had an u/s the morning of his birth and they were estimating he would weigh 8 lbs 12 oz or so. He was 7 lbs 11 oz when born 6 hours later. But, his head circumference was in the 90 some odd percentile at birth and my husband's family is known to have large heads. I have concluded that they estimate weight based on head circumference, which is why they typically are off my a pound or so in either direction. If you or DH have larger heads, then I would be less concerned about size estimates.