Hokay.
First of all TSS doesn't really happen anymore, ever. For your viewing pleasure, I include
The Wiki Article which explains that they don't really know WHY TSS happens with tampon users, but suspect it has something to do with ulcerations in the vagina caused by using a tampon with too much asorbency.
Secondly, if you're having abnormally heavy periods (like, bleeding heavily for more than two or three days) you need to go see your Gyno to rule out any problems and perhaps to go on hormones to lighten things up.
As to the leaking, I suggest getting a
Diva Cup, the greatest period invention EVER. And wear a pad on top of that.
Blood stains are usually best treated right away. Ones that have set in can be helped along by spit (yes, spit). Enzymes in your spit break down blood... although I have no idea why. But, from expirence, I can say it works