Congrats on day 7 vilang! It's tough right now and your determination is showing through. It can take much longer to recover from even light exercise during a fast at times, it sounds like this is one of those times for you. Don't be afraid to lie down for a while during the day if that's what your body is telling you it needs.
And if you wish to stop drinking water for the duration of the acid reflux a day or two without it certainly would not do you any harm. Again so long as you are listening to your body you can't go wrong. :)