If you cannot tolerate any fluids at all, then go see the doctor. The urine dipstick test can suggest if you’re dehydrated. Other signs include reduced amount of urine your produce, dry mouth/skin, etc.
By the way, just from experience, chocolate and snacks and sweet drinks usually make the nausea worse. Try going for hot ginger tea, plain crackers. Also, get medicine from your gynae (diclectin). It helps the nausea a lot.
Hope you feel better soon:)