I'm sorry for your pain and sorrow. You certainly are not over-reacting. I find like Lil said things strike us deeply at different times of our lives, I've started to learn that it's not always worth questioning why the emotions are there but accepting them and coping with them as best as possible.

Just a suggestion... take a few minutes to drop her family a card, if you know how to contact them - they will be touched to know that she touched your life.