Drinking way more water than normal

So I was wondering if I may have anything to worry about? I already called and left a message with my doctor. But today I've been awake for a total of 6 hours (I took a nap) and I've already gone through 3 bottles of water and a tall glass of orange juice. I don't normally drink this much at all, I've been increasingly thirsty. I'm also 37 weeks pregnant for the record, can anyone help??