My advice is to decide how you want the session to end so that once you get through the feelings you need to share and try for the clarification you want, you end on an empowering note. I believe if you give yourself a small ritual conclusion, it will help soothe your upset feelings a bit and help you move forward. You gained a great deal it sounds like in your prior years of therapy with her- I know the relationship predates your mother's death after which she may not have been the best person to help you, so... if you can think on how you want to leave the entirety of it for a new phase in your life, sort of like graduating a tough college program.... it may help.