Well, since you mentioned that your T knows that you were triggered and you talked about it...I wonder...had your T talked about the passing of your pet? Did she challenge you on how long you expected your dog to live?
If so, perhaps she is trying to calm you with rationalizing.
Emotions aren't very rational a lot of the time. They simply are how we feel. It isn't healthy to stuff our emotions away and pretend that they don't exist. In my experience, our emotions are simply emotions. You can allow yourself to feel ____ for 20 minutes, and then try writing (or typing) about it in a journal. Draw a picture. Make a painting. Work with clay. Dance to the opposite emotional music. (Happy music) Color or cook.
The important parts are allowing yourself to feel sad because ____, write it out as clearly as you can, and then let it go.