Possibly a form of slow torture

Took my 3 hr glucose test at 6:30 this morning. Got home and ate and drank water and passed out. Now at 2:20 I feel awful! Super upset stomach and I'm really lightheaded. This doesn't mean I'm going to fail right?! I think it's kinda dumb for them to wait 2 months before my due date to find out if I have gestational diabetes...it's a little late isn't it?