How do you deal with someone who doesn't respect your personal space and whenever they are in it are insistent on you caring about their problems?

There is this one girl, predictably in high school, who insists upon just that. I don't want to be too confrontational since it affects other people at work, but on the other hand it's annoying as fuck, and I don't have the energy to care about her problems...

Any suggestions/advice? What are some social skills one would use here?