Girls, Girlfriend doesn't know how she feels and wants time to think. What should I do?

Anonymous
I've been dating someone for 5 months (She's 33 and I'm 30) and things seemed to be going well until last weekend when she suddenly tells me on the way home from a double date with her friends that she isn't sure how she feels about me and needs time to think. This took me by surprise because:
-She introduced me to her mom 2 weeks ago. My girlfriend then invited me to Thanksgiving, and asked if she could come to Christmas with me.
-She recently talked about a future with me and even mentioned that when her lease is up she would want to move in together (I thought it was a little soon, but went along with the idea).
-She calls me all of the time to talk, and asked me to stay at her place 3 times this past week.
-She was telling her friend who we double dated with how great things were going the night before we went out with them. Then told me.
-she has been very affectionate the entire time and slept with me the night before she told me she was confused.
-There are a bunch of other reasons similar to this that would make one think there was a future.

After telling me how she is unsure about her feelings for me, she then asked if I still wanted to stay the night at her house. Seems odd, right?

I tried to be respectful and give her space on Sunday and Monday, however she called me both days and acted like nothing was wrong. On Sunday, she even asked if I was avoiding her since I didn't call her. Still not sure what she was thinking with that question.

How is it that someone goes from seeming to be very into a relationship to suddenly "not sure"? She and I are supposed to talk in person some time this week. Any advice for how to handle the conversation of things to say/be aware of?
Girls, Girlfriend doesn't know how she feels and wants time to think. What should I do?
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