3 hours glucose tolerance test / gestational diabetes

Fion
I did my 3 hours glucose test yesteday after I failed the first one with 151mg/dL.  It was a terrible experience. The first half an hour I was fine then I got so dizzy and nausea for the rest of the time, thought I would pass out.  The lab tech had me lay down and rest. 
So I received the results today, got excited when I saw the fasting and 1 hour result which I am within range, 70mg/dL and 144mg/dL.  However when I saw the 2 hours it is 162mg/dL and the 3 hours even went up to 192mg/dL.  
I looked at the standard... It should go lower after the one hour. 
Does this happen to anyone else ? And do you get diagnosed as gestational diabetes ? What's the treatment ?
I am so upset and worried right now =[ any comments will be great.  Thank you!