Help a brother out (literaly)

I guess this is a question of diagnosis, I live with my sister, which is more like us and the significant others. However, I believe that she has an anxiety disorder and doesn’t realize it. She displays personality traits of perfectionism, is a major hypochondriac and a germ phobic, she has traits of obsession, and criticism sensitivity to name a few. The problem is that she is really driving a spike in our relationship; she is really negative and is always walking around complaining about something. She had problems with my girlfriend living in the house because supposable it was like an evasion (a girl thing, she described “two girls living together like that doesn’t work.”) Due to this my girlfriend moved out because she saw that this situation just wasn’t working, which of course but a strain on our relationship because she doesn’t enjoy coming over to face the “crazy girl.” She also has an issue with control, which is quite evident in her boyfriend and also her daily routine. Cleaning seems to be her “thing”, she is definitely obsessive, once she loses control of a situation or is clearly not getting things her way it’s clean, clean, clean. My question to you is can any of you relate to her and also what should I do to clear the air; hopefully finding a solution to help her realize what is actually going on?