I'm so sorry for your tremendous loss.
Please don't blame yourself. I know it's hard, but I believe what you said - that Tavia was calling you home, and wanted to love her favorite person in the whole world. It sounds so much like how my aunt lost her cat. They were playing and loving on her bed when Misty kinda twitched then ran into the headboard really hard. Janet (my aunt) had to know what happened and had an autopsy done. Turned out Misty had a severe stroke, and running into the headboard had nothing to do with her death at all. It does sound like there was something else going on - a heart attack, a stroke, an aneurism, any number of things.
I'm glad, though, that you were with her when she left. You were able to help her by calming her, and that means a lot.
Rest peacefully, Tavia, and look after your Meowmy. Her heart really hurts right now.