Why haven't i had a period in 7 months?

Many possibilities: The most common reason for this is pregnancy, but presuming you aren't pregnant there are many possible causes, such as thyroid imbalances, stress, excessive exercise, being underweight, etc. I advise evaluation by a gynecologist as it is impossible for any doctor here to answer this. Get a conventional evaluation, but be aware that homeopathy, acupuncture and herbs may help.