Well, rats. Was it much water? You are allowed a small amount the morning of your test. But otherwise, ugh. You aren't supposed to drink as you know. Did you tell the test administrator about the water consumption? They may have you do it again.
Don't feel bad. I once ate a peanut butter sandwich before a glucose test. I failed it. That was the shorter glucose test. If you fail, you have to do a long one which is several hours. I did it to myself for not reading the directions properly. :>) Happens to the best of us.
So, I'd tell your doctor about the water. See if they want you to re test.