If you need sleep, then sleep. Don't sacrifice eating to continue working. If you start feeling irritable take a break for while.
Your well being is an integral part of whatever you are trying to build. It is absolutely necessary to prioritize your wellness not only for your work, but just for your day to day.
We all make sacrifices for what we believe, and that's cool. However your wellness should not be one of them.
Do whatever you need to do to maintain that. It's fucking worth it. Trust.