Passed glucose still on diet?!

Do

I failed my 1 hour by 5 points. My Dr said to eat and drink like normal before the test so I did.

I passed my 3 hour test and wasn't even close to failing yet when my nurse called she said my doctor wants me to avoid all sugar and carbs!

Is this silly??? I mean....I looked online at my scores. It's not like I was even cutting it close.