She is having unstable feelings. She doesn't know what she wants. She wants to be close to you so she is sweet, but not too close so she is nonchalant. It looks like she is having trouble finding the reasonable medium to be in. When you talk to her, tell her that you are confused when she acts differently towards you day to day. You want to know how she really feels about you. If she can't figure it out now, maybe she needs some time to think about it. Until she figures out what she wants, you can protect yourself by not giving too much.