Gestational Diabetes

Sooo... I did not pass my 1 hr test. I am so disappointed 😞. I have my 3hr in a couple weeks and can’t have anything after midnight or during the test, not even water. The drink always makes me nauseous.. I am 40 y/o and this is my fourth child. I have never really had too many issues like this with my other children. I’m nervous. I am already measuring quite a few weeks ahead and they’ve already told me they won’t let me go past 38 weeks. I think no matter what I am going to start a GD diet. Any thoughts? Or suggestions?