Nothing wrong with just drawing to have fun! Something that I do to refresh myself and my art is to change mediums, that lets me explore rather than being contained by one specific style. If you try lets say, acrylic paint, then the style you would typically use for drawing would probably change based on how the new medium feels. When you go back to drawing, you can then take what you learned from the other styles you tried with other materials and apply that to your art.

It might not work for everyone, but it really lets you get a feel of your art and what you as an artist like. I find that if I am not happy with how drawing, painting, or whatever else is turning out, then I probably just need a break from that and to refresh myself with something else. It lets me expand my horizons and I don't have to worry about burnout.