Late / Erratic Menstruation

inccmd

I had tubal ligation in 2011. I am 48 and had been pretty regular though getting heavier before all this. Ever since my tests & diagnosis in Mar/Apr, my periods have been weird. Very heavy, stopping then starting again. Surgery in May interrupted it, and then it started up again a week later and completed its cycle. This time around, I'm very late.

I want to put it to stress since I did have tubal ligation and pregnancy unlikely. Anyone else experienced odd cycles as a result of the stress of testing, diagnosis, surgery etc? I am not having chemo, but I start radiation in two weeks.