Don't worry & don't listen to others who don't allow you to drink. They will come up with 1001 reasons, their friends lah, relatives lah this & that has backache lah, baby got stomachache lah, all the nonsense but really has nothing to do with water. See the ang mohs. They drink coke right after birth & still healthy.
Drinking less or drink ice cold water is a myth and has been debunked. Drink less & you'll have water retention. Also, cold water will become the same temperature as your body once it enters the stomach. So drink up. You need to drink more fluids even during confinement to boost your milk production & help with weight loss.