From time to time we all may experience being overwhelmed. It doesn't even need to be a burnout. You just feel like you have too much on your plate, not enough time and energy. It could be a big complicated task you are working on or many smaller things you need to do that weighs you down. The mere thinking about it is exhausting. There are ways to overcome this, however.
The first and the most effective countermeasure is offloading it from your brain. You don't need to worry about it constantly as this is a waste of your mental energy. Simply write it down somewhere visible. Once it is there, your mental resources are freed and can be used to actually get things done.
Now if you are working on a big task, often you get overwhelmed by many different smaller things you need to do to finish it. I found it very effective to break that big task into small pieces while writing it down. The smaller tasks should not be divisible, so they would not require your memory to be used to remember what still needs to be done. So, the technique is to write down all the steps necessary to complete the bigger tasks and simply do them from top to bottom one by one. If you find that there are more things to do, just add to the list, but finish what you started first.
This should already be enough to get you going but don't overwork. Rest is very important. No amount of techniques will help if you are simply too tired. Get a good night of sleep, eat well, and have regular breaks. Some find the Pomodoro technique helpful to remain productive throughout the day. However, your body will tell you when it's time for a break, you just need to listen. And when you do, step away completely from what you do to reset. Go outside, talk with your spouse, play with your pet, etc. Usually, this is the time when solutions unexpectedly come to your mind.
Overcoming being overwhelmed is possible. Offload as much as possible, break it down into smaller manageable pieces, and make sure you are well-rested. Good luck! 🙂