i'm sure it's nothing to worry about. my periods are sometimes early...a week even! however, if you're really concerneced you should go see your doc!
btw, do you live in a house in full of women? if you live with alot of women, your hormones sync with each other and your periods with coincide together. maybe that's why!!??
anyway, i hope it's all fine!
You could be alittle stressed no biggy. If your worried that you are pregnant, probably not their is such a small chance of that but if you are really worried about it take a test. Also sometimes your body does weird things to make up for a change in your life. Is it possible you could be pregnant? Sometimes you can have very light bleeding and be pregnant or you could be miscarring the baby and that is why you have such a light period right now. If that is the case it will get really heavy soon and you may experience rather bad cramps.