No regular period since february 14?

Likely cause: Am i correct to assume this is since feb 14th this year? If so nothing to worry about as this has just been one cycle (give or take). If this has been since last year, then some form of a work up is warranted. One of the most common causes of changes in menses in young women is related to how much exercise they are doing , in relation to calorie intake. Hope this helps.

Missed period?: Pregnancy is certainly the most common reason for a missed period when sexually active. An anovulatory cycle (your ovary just does not release an egg that month), thyroid conditions, rapid weight fluctuations, extreme exercise, stress, etc. Are all other causes that may be possible. If you are having sex unprotected, check pregnancy tests, otherwise if you miss your next one too, see dr. For eval.

Irregular periods: There are may reasons that could cause irregular periods in a young female. The most common is pregnancy. Others include: stress, skipping ovulation during a period of time, hormonal problems, anorexia. It would be wise to consult your primary care provider and get evaluated in order to find out the reason for the irregular periods.