I got my 4 day period on the 6th of october, then on the 20th of october i had got bleeding again for 3 days, i didn't need a pad, what could this be?

Your hormones are in: .. flux for some reason. Irregular periods and spotting could mean you may have some hormonal imbalance that could be affected by many different factors, including age (if approaching menopause?), nutrition, illness, exercise (or lack of it), body girth, psychological well-being, stress, season, or simple fluctuations of other related hormones (thyroid for example). U should check a preg test 2.