I'm bleeding exactly on the day of expected period. it's usually a lot earlier. could something have changed?

Absolutely or not.: Periods are cyclic and are determined on a woman's health and hormonal status. . The cycles are generally irregular due to bursts of hormones trying to get the ovaries and uterus prepared for child bearing. Usually in our twenties, the system is regulated. Oral contraceptives alter the system. Irregular use of oral contraceptives a reason for changes. In our thirties the system may start changing.