cycles are considered normal from 21 to 35 days. However stress can also make periods irregular
. Other causes of irregular periods could be due to hormonal imbalance, stress, chronic illness, polycystic ovarian disease, thyroid gland disorders or diseases, pituitary gland tumors or cyst, galactorrhea, prolactinomas etc.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided.