Even when you're still knee deep in a burnout, it can be helpful to know what to expect when you're out again. This is a subject that we can approach from many different angles, which we will. Yet the most important thing is you getting some perspective. I am aware that you are feeling bad and that your negative emotions need the space they deserve. Nevertheless, let's give the positive some space too. We'll go slow.
From a rational point of view our negative emotions have a function. They serve as the signals that guide you to a better life. The problem is of course the emotional point of view. Maybe your mind knows those feelings are functional. But you still actually feel them. And it ain't nice.
After the burnout has subsided they will not be gone. You will most likely still feel the same negative emotions you are now feeling during your burnout. Crucially though, you'll have learned to better recognize and listen to them. They are still inside of you but you make peace with them, even use them. Your alarm system has had a major upgrade. You'll be more sensitive to warning signals, which can work to your advantage.
Your burnout can be viewed as a training ground for being able to much better deal with the negative than you ever had before. Right now however, you are in the middle of the exercise in that painful gym of the mind. Like lifting those weights when you are already very tired, the hurt will be very real for you. But like in the gym, that can also be viewed as kinda... cool.
You are strengthening yourself, through the hardship. The very definition of strength. And unlike most people, I'm not going to give you advice on how to deal with that hurt. That is your personal journey. I can however tell you how to alleviate some of it: go physical. You are free to experiment with anything that gets you out of the mind and into the body.
You choose between shaking, scent, martial arts, breathing, a shower, a walk... you get the picture. This will not solve your problems but it will soften them and make them easier to tackle. After the burnout, other problems will of course enter your life. This time around however, through your emotional pain, your mind and heart will be trained and ready.
That's the perspective. You're not there yet. Give it the time and space it needs, however frustrating it may be.
And of course, as ever, take it easy.