I read a good book all about water, In it it says that when we dont get the amt of water we should have for a long period of time, our natural sense of thirst actually sort of goes away....so once you start drinking the proper amt of water, your thirst signals come alive. I also noticed this big time! so, even tho you are drinking more water, you seem to be more thirsty. Its actually a good sign, because the majority of people have lost their natural sense of thirst. Thirst is a good thing to have because it reminds you to drink your water, when the thirst sense diminishes you tend to think, "well, i'm not thirsty so I must not need the water" when actually you really do need the water. your body is crying out for it
also, caffein actually causes your kidneys to excrete more water, so the coffee might be causing you to be more thirsty.
Those who think they have no time for bodily exercise will sooner or later have to find time for illness. - Edward Stanley, the Earl of Derby, 1873