Hello. It is not normal to have irregular periods. Most often there is an underlying cause which leads to hormonal imbalance, which then cause irregularity in menses. Since, you are not pregnant (urine pregnancy tests are pretty reliable), I would suggest you get further evaluation done in the form of blood tests like TSH, hormonal levels and imaging like ultrasound of the reproductive organs. Conditions like hypothyroidism, polycystic oVarian disease, etc can be ruled out by these investigations. These can be readily treated with almost no longterm effects. Hope this helps. Regards, Dr Geeta