Despite how it may seem there's no chance your company will die or suffer any irreparable harm in a week. Just do it.
When you come back have a discussion with your co-founders. Try to talk through (calmly and without resentment) the problems you see. Focus on finding the best solutions to the problems. Don't get into arguments about the past. Everything before is water under the bridge. You will have to accept that certain things probably can't be fixed, and that's okay. Fix the things that hinder your company's ability to succeed.
Also, make sure you sleep enough every day. Don't skimp on sleep at all. Nothing will make you burn out faster than chronic sleep deprivation. Everyone can get 8+ hours of sleep per night if they make it a priority.