temperamental cat

My cat (the Lover) was named for reason. She has always been the Most lovable little girl I have ever met. We moved in January and she adapted well. However, when I got home this evening from babysitting my nieces she has been acting like "church" from pet sematary. She actually blocked me in a room as to where I had to shoo her with a slipper to get past her. When I first walked in she woke up and gave me a cat smile. I pet her a couple of times and about 30 seconds later she was acting like I've never seen her before.

Any time a cat changes it's behavior so drastically like this, I would think it's time for a Vet visit. 

Are there any other changes in her...is she eating, playing, sleeping as normal?  Is she still acting like she doesn't know you and trying to attack you?