When people begin healing, from loss, from burnout, from an old wound, they often expect a straight line. Each week a little better than the last.
Then a bad day arrives, and they feel they have gone back to the beginning.
They have not. Healing is not a line. It is more like a spiral, or the seasons. You return to similar places, but each time you are a little different, a little stronger, a little more able to hold what you feel.
A hard day in the middle of healing is not proof that nothing has changed. It is part of how healing works. Notice how you respond to it. Often you will find you recover faster than before. That is progress.