My H is doing the same thing, where he is happy one moment, then it is followed by him acting sad and distant or snapping at me. I wouldn't take that personally, as they are going through a lot of stress right now.
If you said she was not opening up to you before when you talked, and now she is doing that, then I see that as a positive thing. Maybe she feels safer now talking to you. Is that what she was missing from you before?
M: 8 yrs T:14 Twins:7 S:5 BD:'NLILWY': Feb/2013 Mar/Apr/May: MC June: "living in limbo" Sept 12: H moves out Oct 20: reconciling Jan-Feb 2014:MC Feb 2014: separating, and H moved out.