I can't do this anymore

[glatt]

You're not fucked.

You just need to do the work you can do in the next few hours, and then go home for the day. You don't have to do it all right now.

Everyone is calling you? Just answer the phone and talk to them one at a time. They are giving you more work? Fine. Just add it to the pile. You'll get to it when you get to it. And you won't be rushing. Just focus on the work you need to do for the next several hours until quitting time.