gestational diabetes in

I am 32 weeks 4 days pregnant I did my gestational diabetes test yesterday and they called me and said there a was a little sugar in my blood and want me too do the 3 hour test any advice if I do have gestational diabetes never had it before this is my third pregnancy!!! She also measured my belly and said he is measuring about 3 weeks ahead I go for al ultrasound tomorrow cause she Said I have an over size baby she is thinking he is 6 to 8 pounds I am worried really scared I don't know what to do I am worried about my baby😰 I have never had this with any of my other pregnancy I haven't really gained any weight only about 8 pounds thru out my whole pregnancy 
I took the gestational diabetes test about 4 clock yesterday so could that be why I had some sugar in blood any advice I would appreciate it thank you