I'm a 22 year old who is having very light bleeding episodes rather than a normal period. what could the cause be?

Stress: Stress most common cause of menstrual irregularities. Keep a record of you r cycles on a calendar makes it easier to follow and can chart other issues in your life as well to better see any correlation

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