Communication is always important in relationship and in order for you to find out what is going on and where her mind is at then you need to talk to her about things and get it out in the open. She may be stressing about everything in her life and it may not have anything to do with you. She may also think that if she doesn't chase you away you will run away anyway because of how hectic her life may seem. It's important to show her that no matter what you will respect and care about her and it's only been 6 months so give it some time and ask her what she needs for you to do and if she says nothing then leave it at that but ask every once in a while. Try giving her some "Me" time this may help her recollect her thoughts and be stronger emotionally to deal with everything she has to deal with on a regular basis.