I'm in the exact same boat. It's hard to answer why I left working for a company I had spent so many years with to new employers during the interview process. I know to say pleasant things and give a positive impression as well as ensuring that I don't speak poorly of past employers, but inside, I'm still reeling from the past. It's nauseating to try to come up with the positives when in reality it was the total opposite experience. And I have to walk away and pick up the pieces. No recourse.