What do you do when people "vampirise" you?

I live currently in a flatshare and have a female flatmate who is a so called "vampire", she has psychological issues, cannot be alone and stalks people in the flat just to get attention. It is extremely difficult to set boundaries with her, as she seems to "suck" energy from you even through the walls and closed doors. I cannot move out at the moment. Is there a way to protect oneself against such vampirism?