Three hour glucose test

Brittany • Just got married in March. Expecting our first baby April 2016! Already a momma to 3 fur babies.
So I failed the one hour by about 50 points, but I don't think they gave it to me correctly. They gave me 10 oz of glucose solution and about 20 minutes to drink it. I did the test at labcorp instead of my doctors office, where they give you five minutes to drink it. Anyway, I take the three hour test tomorrow. Any suggestions on what to do other than fast?