drinking water

so since i got pregnant my stomach doesn't allow me to drink water.. it's like i drink it then run to restroom to throw up.. and i hate it!!.. and on top of that my fiance is always telling me how our baby is not going to make it because i don't drink any water.. it like he thinks i don't want to drink water.. he doesn't understand that i can't!!.. my doctor says i just have to keep myself hydrated and i do drink other stuff.. i know he's worried but some of the things he tells me make me feel really bad.. so i want to ask.. is it really really bad that i do t drink water??