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Changes in period pattern, flow and duration could be affected by stress, changes in lifestyle or exercise levels, anemia, hormonal derangements, thyroid hormone imbalances, PCOS, ovarian cysts etc. The exact cause can only be made out after careful evaluation. Consider visiting your doctor/gynecologist for further examination and investigations to look for the underlying cause. Treatment as appropriate (based on the examination findings and investigation results) would be started to help you to regulate your periods. Consider being in regular follow-up and monitoring of your treating gynecologist and report any abnormal/new symptoms immediately. Take adequate rest. Drink plenty of water. Maintain healthy diet and lifestyle.
Take care.