I run and workout every day and haven't had my period in about 8 months is that normal for my level of activity? i am 16 and was never irregular until now

Even : Even though extreme exercise can cause an irregular period, moderate exercise should not. The other reasons besides exercise that can cause a woman to miss a period are: stress, diet, pregnancy or a hormone imbalance such as with a thyroid disorder or polycystic ovarian syndrome. If you continue to have an irregular cycle, you should give your doctor or your ob/gyne a call. They should make sure you don't have a more serious medical problem causing you not to have a period. Good luck!