Is there be a problem if on an 8 day menstrual cycle you periods begin with spotting and disappear by 6th day and on 8th day again there is spotting?
This would only be abnormal if the spotting on the eighth day is bright red.
Actually, I have always happened this to me - bleeding for 5 days, not bleeding one day, and then bleeding bright red and a lot for another 2 days. What it meant for me was that I have an inverted (heart shaped) uterus. This causes the disruption in bleeding. At least that's what I was told.