Does this mean she doesn't like me?

Ok, so this girl I like flirts with me a lot and gets jealous of other girls, but everytime I show her affection, she immediately acts like she could care less and hates me. Today as an example I asked her if she wanted to come with me to a party later and she said she had a family gathering to go to. When I asked her if she would tell me if it was another reason, she said maybe. Then later I told her I was going to see a movie with my ex and she was mad. She was like "ok" in a very disapproving voice. I said to lighten the mood "hey it could've been you" and she just glared at me and said nothing. I don't know what to think.?