hello. if u previously had normal cycles and are facing this problem for the first time. you could wait because sometimes it can happen even in normal instances. if it persists, suggest you to get yourself checked out by your gynaecologist and get a hormonal panel and USG done to rule out any problem. additionally would suggest you to eat healthy and dnt take stress. because irregular food habits and stress etc can also cause this problem. all the best.

may be still ur hypothalamic pituitary gonadal axis is not well established or anovulatory cylcles physiological stress contact ur gynaecologist.