Welcome to PC

Feelings are feelings and worth embracing and acknowledging, they truly aren't right or wrong, as they are feelings. Many times, those with depression will talk about sitting with feelings. They come in handy in sorting out needs and wants where relationships and life are concerned.

I'm curious, as it stood out to me, about how mother's day came to be since your parents are separated. Personally, my divorce clause which is relatively standard barring a couple points, states that mother's day is spent with the mother and fathers day with the father where visitation is concerned. Since it sounds like an important moment in your feelings about the conversation I'm wondering if this is a touchy topic for her personally and your moment with her was amplified over whatever it was that brought you to your dad's family for such a day?
Worth considering since it had an effect on your emotions.