School is historically quite damaging to such things. Took me years to start reading fiction again.
This also assumes you have not simultaneously had a drop off in interest in a concept*.
*creativity in what is the next thing -- composing music, writing poems, writing long form stories, photography, sketch comedy, long form video, science/engineering solutions (truly a thing despite some not thinking it belongs) and painting are all quite different concepts in their execution.
I sometimes find if you have a practical use for something it can jump start it, for instance don't paint a painting for you and instead painting some restaurant's menu uses many of the same skills, similar can apply to anything. Good luck finding a practical use for sketch comedy.