LOL, not much you can do! Don't panic. See if you can fit in a glass or two or water before bed (maybe not too much else you'll be up all night!) then make sure you drink lots tomorrow. Be warned that one day without enough liquids might make you more prone to being constipated a couple of days from now, though!
Id try to drink plenty before bed , obviously not drinking all the water you can as that not how the plan works. Then tomorrow drink more and try catch up over the next 3 days. As the previous post said you maybe a little constipated this week now
I have this problem as I drive a lot and font fancy knowing most of the people on the service stations on the m25 lol so I try and get a good 2 litters down me in the morning or the moment j get in, I know how you feel at time life takes over me, it literally at times is a battle xx
I have the opposite problem, I can't stop drinking & have to limit myself to 4l a day. I'm tall though so need to drink more. I panic about even driving somewhere without a bottle of water with me!