No, "I'm sorry you" is not correct and it's completely confusing. I wouldn't know what you meant. It isn't a normal English phrase.
Some natural replies would be:
"It's OK."
"It's nothing."
"Don't worry, it's OK."
"Don't worry, it's nothing."
If you had yelled "Ow!" or "Ouch," you could add "I'm fine."
"Don't worry, I'm fine, it's OK."