I'm the same way, I'm 9 weeks and I can't drink any water at all. It just upsets my stomach and makes me feel super sick, maybe your still experiencing your sickness. Sometimes you can experience it longer than the 1st trimester
Strange.. Have you tried drinking inbetween meals instead of with your meals? And maybe you could try drinking lemon water or other drinks throughout the day to keep you hydrated and just having a big glass before bed so you're staying hydrated but you will just fall asleep so your stomach won't be upset, although it will probably make you have to get up to pee in the middle of the night!