I found this info on another site about implantation bleeding:

Implantation Bleeding
This is normally light and not as heavy as a period. It occurs when the embryo is embedding itself in the wall of the womb, and is not considered a threat to your baby’s wellbeing. Bed rest is advised to reduce the flow of blood to your womb that occurs when standing.

Bed rest??? :-s Well, I have been exercising like a fiend because I am trying to lose weight so I hope I haven't done anything to jeopardise a possible pregnancy. I have some spotting in the last 2 days and I am only 5DPO so I am hoping it's implantation.

The confusing thing is that some people say that implantation bleeding occurs just before AF is due yet others say it happens earlier. I guess I will find out soon enough but I am impatient! ](*,)