Light periods

When is a period considered to light to be normal. Each cycle mine are constantly getting lighter, more painful and full of clots. Day one of my period I bearly fill 1/3 of a pad all day. During the night hardly nothing day two. Spot of a 50c (Aus) coin and after that it's a waste of pads or even liners because there's not much there. Am I over reacting or is this considered normal for light periods. Thanks