I am not sure of the metabolic process, but the same thing happened to me last fall, when I was stressed from my mysterious illness; I lost weight and I had high bp. Mine is also usually 110/70. There was no medical reason for either of these things.
I understand what you mean. I was secretly pleased with being so skinny, but really, I was worried about losing 5 pounds (which on a five foot one inch person is a lot).
Maybe, after all of the stress with your parents and your dad's passing, it is starting to hit you physically?

Robyn