I wouldn't call her crazy. It sounds like she's suffering. OCD traits with the washing, possibly, but it's hard to know what drives that. The knife situation sounds PTSD, triggered by your words that reminded her of something in the past. Honestly, though, it's hard to know. If she weren't avoiding you, and you had more of a friendly relationship, I'd suggest asking her if she's okay, but she seems to be so fearful I'm not sure that's a good idea.

I hope she gets help.