There are two types of people with obsessions in therapy.

1. Those obsessed with the therapist
2. Those obsessed with the therapy and/or talking about themselves

Though I would say I was fond of my therapist, it was more the latter in that I really enjoyed bringing up my innermost thoughts. I miss that more then I miss the therapist, not that I don't miss her.

btw, I did go though the odd day where I'd think about my therapist a lot. But mostly, it was about me, what I want to talk about, how we're going to find a solution etc...

When you think about you're therapist too much, that could be a way of escaping other things that are bothering you. It's a bit like someone who gets addicted to say drugs or alcohol, videogames. If you're addicted to your therapist or the therapy, think why that is.