Keep going! I have had both positive and negative transference with my therapist. My brother is a clinical psychologist and said that transference is a sign therapy is working. She needs to see this side of you because you might be reacting the same way in other relationships. Once I started realizing what I was doing, I would point it out to her. I just got to the part of telling her I hate that she affects me in any way because I was determined not to let my mom think she could affect me in any way. All of my positive and negative reactions to my T. have helped her see what my childhood was like and what I was missing. And, yes, you can realize it's happening one session and not realize it in another. Sometimes I can totally point it out and sometimes I don't realize it's happening. It's pretty fascinating.
Keep going and talking to her about it. Most T's have seen this before and, as I said before, it allows them a glimpse into your past.