I also notice when I don't get a lot of sleep I tend to smell or when I wake up several times a night and it's not a restful sleep I smell. Five hrs. is usually what I sleep a night and 6 max if I haven't slept well in days.
Stress and certain foods also trigger the fecal smell but I'm slowly adding new foods to my diet to see which will agree and which will create fecal odor.
Haven't had blood work but have to go for my yearly checkup in a month or two and see how that goes.