Having an abnormal menstrual cycle is very common, and certainly Not every woman has the perfect 28-day cycle with ovulation on day 14.  but there could be signs things are not quite right:

You haven’t had a period in 2-3 months or longer. Skipping a period isn’t always cause for concern, but if it’s been 90 days or longer since a period and you aren’t pregnant, then there could be an issue. Your period or menstrual cycle varies each month. Do you notice that nothing seems consistent with your menstrual cycle or period? From PMS symptoms to bleeding, to how long your periods last, if they aren’t consistent, there could be something else going on. You have intense cramping or bleeding throughout the month. In addition, if you have pain and spotting or bleeding throughout the month, even if it’s not every day of the month, it might be a sign of endometriosis, PCOS, or fibroids. You have intense cramping or bleeding throughout the month. In addition, if you have pain and spotting or bleeding throughout the month, even if it’s not every day of the month, it might be a sign of endometriosis, PCOS, or fibroids.

Apart from mental stress, irregular menstruation is caused by several other attributes including fluctuating body weight, sudden weight gain, excessive strenuous physical workouts, emotional challenges, medication side-effects and underlying chronic diseases of diabetes, hypertension.

vastly boosting reproductive wellbeing and regularizing menstrual cycles. Comprising stationary poses, flexing movements and breathing techniques that work in synergy to instil overall wellbeing, Yoga is a time-tested tradition that offers instant relief from stress, relaxing the body, calming the mind and activating reproductive operations in women. 

Yoga has also been shown to reduce menstrual pain and emotional symptoms associated with menstruation, such as depression and anxiety, and improve quality of life in women with primary dysmenorrhea.

https://courses.yogabelliesschool.com/courses/seasonsandcycles