Welcome to Healthcare magic.
Soaking three pads full at 9 weeks is too much for this early pregnancy
. I am not in a position to give you reassurance, you will have to wait for scan to find out out your baby's condition. It is good that you have no pain & did not pass any clots.
is not generally considered to be harmful so donot blame yourself & hope for the best. Although you should avoid this in future if your scan comes out normal.
Wish you best of luck.