Pfft, you can do it. You have a cheerful personality. You cannot let your art be sad.
You teach Art how you feel and then Art will teach you how to feel. Art is a good way of keeping a state of mind. If you wish to be upset then through art you can draw powerful images, write meaningful text to create that mood for you.
At the same time, if you want to cheer up, you do the same thing and your art will help you cheer up.
It's a matter of what you want! Be selfish and be confident in your art.
