Yes, you certainly can get addicted to second hand smoke from crack. It is a very powerful drug. Having been exposed to it for 2 years then for certain you are addicted if you are expericing the withdrawal symptoms that you spoke about.
Until you leave the premises you are sharing with her there is no way for you to avoid exposure to this. Crack smokers are not the best people to have as roomates as they tend to go through their money buying more crack and when their money runs out, they go after your money or your stuff and sell it to feed their habit. Watch the tv program Intervention to get a handle on crack heads and how they "see" the world. They will rip off their own parents, grandparents, friends, etc. for their next stem of crack.
If you want to stay and help her, it's going to be a very steep uphill battle to be sure. If you wish to leave, I can well understand you doing so. She will not stop cold turkey unless she is arrested and goes to jail where she can't get any drugs. Rehab for crack heads has a high rate of failure due to the drug's inherent physical and psychological hold on the mind.