I hear ya, Maggie. It doesn't have to be like that though. I'm no success story- yet, but I know exactly what you're going through. Depression and shame all day until you rationalize your next drink than magically, your energy and excitement has returned.
To get through the first 2 nights, I sort of treated it like I had the flu. I'm sick, I need to go straight to bed. Planned on being up most of the night so I planned on watching a lot of tv, sweating a lot, and being tired in the morning. All was true, except I felt pretty amazing not being hungover and I didn't have to shame myself and say all the terrible things we say to ourselves in the morning.
I hope you're able to have a sober night tonight.