Who am I? A kidnappee story

If you ask me my name nine years ago, I would have said Samantha Elisabeth Brooks. Sam Brooks as I was commonly known. Now if you asked, it's Catherine. Catherine Louise Montgomery. Cat Montgomery. Truth be told I was hiding for a long time. A very long time. Memories that I blocked for six years are coming back; people I once known are coming back.
Expect I don't know them. At all. Those are Sam's memories. I haven't been Sam in a long time. Trying to figure out who you are shouldn't be that hard. However it's a lot harder when there's two different people in your head.