I would still think that two glasses is not enough of a swing. Periods of high water usage can drastically change how much our bodies require. After a single one hour workout, the recommended fluid replacement can be as high as forty six ounces for some body types and activity levels; that's six glasses of water or well over a full liter bottle. Two glasses is comparatively microscopic. Antibiotics may also be confounding since they tend to come concurrently with other issues and could cause diarrhea.

I'd recommend picking up two one-liter bottles of Powerade* per day and using those as your drink gauge, in addition to your normal diet while you test. It's actually fairly hard to overhydrate yourself except in extreme circumstances, and taking a sports drink should be extra protection. If you find a flavor you like, it can help turn a chore into something you...well something you at least don't hate.

*Powerade contains more potassium than Gatorade and the same amount of sodium. Since most people have sodium in excess and are potassium deficient, Powerade is generally the better bet. Warning: that may be partial rationalization just because my local grocer tends to have it on sale for $0.50 a liter and I like the taste.

Ah, sorry. I missed that.