constant thirst...

Seriously I can not get enough water. I drink drink drink all day but my thirst is NEVER quenched! I'm so damn thirsty and I am peeing so frickin much. I'm sick of drinking and peeing!! I drink probably a gallon a day but that is still not enough!! I feel sick because of how much water I've been drinking but my throat and mouth is so damn dry... I took a pregnancy test this morning and it was negative. But my urine is more diluted than I've ever seen it. Doc won't do tests if I haven't had a possitive test or a missed period. My period is due today but I don't know what to do anymore. I'm so so thirsty. My temp chart is super high. Higher than it's ever been. But I don't have a positive test yet...