Clutter can be a big problem for many people. It can make them feel stressed and anxious because they have a lot of items to take care of at once. It can also be mentally draining trying to decide what should stay and what should go away. Their clutter has been accumulating over time.
So you can't expect to face everything in a day or two. And if even after trying these things that help you sort out the mess you still feel overwhelmed, take a break.