The skinny on hydration

I'm a big girl. 8x8 doesn't do the trick. I have been reading for days on proper hydration amounts. I've used several calculators that all have me drinking 1+ gallons a day. Here's my struggle. If I drink a gallon plus a day, I end up unable to eat at all. I'm struggling already too get the right calories and nutrition into my day (I don't count, but I do loosely track). I'm a little frustrated because I know both are important. I don't know if I can for both goals at the same time.