I'm so sorry for your loss, mossanimal.

Had to think about it for a bit, but yes, I have had such a trigger. (pre-dx, but I can see it for what it was now, because you're right -- they're different). I think you should trust your feelings on this -- you say it feels like the starts of past BP depressions you've had, so keep an eye on it and take positive action sooner than later. (Because we all know how much harder it can become.) Do you have a therapist? Their help could be very useful at this time.

You will be in my thoughts.