My period lasted two days compared to four , (heavy /usual flow) is that normal ?

Probably: It is common for the cycle to vary over time and what you describe is well within the range of normal.

Light period: The main reason for light periods is a change in hormone levels. Causes for what seems to be a light period can include: implantation bleeding in early pregnancy, thyroid problems, eating disorders, excessive exercise, initial periods for a girl, use of an intrauterine device, oral contraceptives & perimenopause.

Yes: Your menses may vary between cycles. If you continue to have the heavy flow(unusual) in the next two cycles, it would be best to see your health care provider for a checkup.