I would guess this triggers a really old feeling within you about being a burden or unimportant. These feelings are huge, I can tell they are overwhelming you right now.

From an outside perspective I can see why T has decided she isn't going to do work related things on her vacations any more. I can tell that it isn't about you, it's about her creating a boundary between her work and her personal life.

This triggers something huge in you. All these feelings about being a burden, not really being worth anything to someone, not even worth caring about.

This isn't about your T or her vacations, although that is the trigger that has tapped into the well of these worthless feelings. But these feelings are not "just" about T and her vacations. These feelings are about all the times you have felt you are a burden or unimportant or a nuisance or an inconvenience to other people throughout your whole life... when you were 3, when you were 4 and 6 and 10 and 15 and 23. All of the times.
Its just that they are all focused on the thing that triggered them up "now".