Retake of 3 hour glucose test

I failed my 1 hour test and had to do the 3 hour test today. I went to the appointment, got my blood drawn first then I drunk the drink, I sat down and started to get hot flashes then I got queasy in my stomach. Basically I thought I was going to pass out because I started to feel so sick. I told the lady at the front desk I wanted to reschedule because I still had 3 more blood drawings to do and if I had got any more blood drawn I probably would have passed out. I reschedule to take it again next week Wednesday.

Does anyone have any advice on how I can get through this 3 hour test without feeling like I'm going to pass out?

When I took the 1 hour test I was totally fine.