Hey there,
Just wanted to add that it IS possible to drink to much water but it is rare.
Here is a site with some info
<a target=_blank class=ftalternatingbarlinklarge href="http://chemistry.about.com/cs/5/f/blwaterintox.htm">Water Intoxication</a>
There are some other sites that come up if you google, but I didn't want to post a ton of them. Basically it says 8-12 eight ounce glasses of water a day is good. Also that it is important to pace yourself when drinking water and not to overload and drink a gallon of water in a short time period.
Also to add it said that water intoxication is more common in infants and athletes, so most likely you have nothing to worry about. I just wanted to throw that info out there just in case you needed/wanted it.
I think it is great that you are drinking that much water in a day. It will definitely help you to keep your lungs a bit clearer and make secretions easier to move and get out of your body.
Lindsey