I'm sad because I no longer believe I can fly as well as Superman.
So you think you can fly, but just not as well as superman can?
Yeah, I can fly, just not as well as Superman.
Superman is a fictional character and humans can't fly without some kind of assistance. If you think you can fly you may be delusional and should seek help.
Do your research, humans can defy gravity if their minds are focused enough.
I don't think that any amount of focus can allow humans to fly, and if you believe that then you might want to talk to a mental health professional. What you're saying is a delusion, and is possibly the sign of a deeper issue.