Can I still flush today if Im already dehydrated?

Day before yesterday I drank epsons just to clean me out. GOt dehydrated from that a little.
Didn't drink much of anything yesterday + had caffeine.

I don't have a hangover feeling today but I know I'm dehydrated.. Every now and then when I pee only like 3 drops come out..which happens to me when I do get dehydrated.

So yeah, even if I drank like a gallon of water today, should I still flush?