Thank you for your question.
Your periods are a reflection of your ovarian function. If the ovary releases eggs regularly,generally once every 25-35 days your cycle of bleeds will reflect that. Having long periods can signal that the ovary is not releasing eggs regularly. This can have several reasons. It depends on your general health, weight gain or loss, stress, other endocrine illnesses, medication etc
In recent years the number of women suffering with period problems has increased. This can be related to a sedentary lifestyle, unhealthy eating habits, exposure to environmental pollutants and excessive lifestyle stresses. This can herald onset of the prediabetic state with raised insulin levels which then makes it harder to lose excess weight. Longterm such things can cause difficulty conceiving, diabetes, raised blood pressure etc. It is important to see a gynaecologist specialising in fertility and endocrinology so they can guide you on how to protect your ovary, your endometrium and general health so your fertility potential remains good. This may require some blood tests, an ultrasound examination and taking on board advice regarding lifestyle changes including exercise and diet.
with best wishes