Abnormal glucose test. Confused

I went to my OB appointment yesterday for my glucose test. It came back abnormal. So I go back in 3 weeks for the 3 hour glucose tolerance test. My doctor was so busy she didn't tell me anything else about it. She ran in as fast as she ran out. She didn't say to change my diet. She didn't warn me about any dangers. I'm confused about this whole abnormal glucose test results. Anyone on here can give me more information. This is my second pregnancy and I got pregnant 6 months after I had my first.