Hi,
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Having variation of +/- 5-10 days in menstrual cycle length is considered to be normal. The change in period pattern could also be suggestive of hormonal imbalances, thyroid abnormality, ovarian cysts, PCOD, etc. The exact cause can only be made out after careful evaluation. Consider visiting your doctor/gynecologist for thorough examination and further evaluation to look for the underlying cause for the changed period pattern that you describe. Treatment as needed (based on examination findings and investigations results) would be started to help you regulate your periods and get pregnant. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.