A good night sleep is a key element for waking up fresh the following day. On average people need 8 hours of sleep. Therefore, if you sleep less than 8 hours the night before, it is very likely that you will feel less energetic and as a result, it will be more difficult for you to concentrate on your work.
Learn to say no
Have a hobby
Having a hobby outside of work makes you happier as well as lets you use different skillsets. It also helps you meet new people who share a common interest with you. Therefore, you can at least talk about something other than work and take a break.
Ask for help
When you are stressed or feel burned out, ask for help. You don’t need to get embarrassed for asking help from your coworkers. Probably, you will reach a solution or finish off your task much faster with two or more people compared to you working alone. Don’t forget that nobody can do everything alone and that is why generally people work in teams.
Use your vacation days
How to Avoid Burnout at Work (Entrepreneur.com)