Why did i start my period a week early & why was it lighter than usual?

i started my period a week early my period is like clockwork every 27 days for 5 days my are always sore a couple days before i start... Well anyways my still ain't sore. And i only bled for three days (alot lighter than usual) the fourth day i didnt bleed at all then what would have been the fifth day i bled... NOW HERES THE THING... When i pee there is blood on the tissue... Not alot but its still there (is that considered spotting)? *WHAT DO YOU THINK IS WRONG WITH ME?