I have this as well and it is built in to how we are designed. Perhaps it is because of how we were raised or it is just in our hardware.

Structure your weekdays and unstructure your weekends to simply include structured things you enjoy. Hobbies require learning and structure.

Or, structure your weekends with unstructured visits with people -- or your significant other or friends.

Regardless, it is imperative to get out of the structured environment and treat unstructuredness as a Stoic goal because life is not structured and you will be very uncomfortable when you have to face the great abyss of what will inevitably happen to you -- you will have your time, the rest of your life, to yourself.