why have i missed my period? i'm definitely not pregnant and not underweigh!

Best Answer - Chosen by Voters

This does happen sometimes!
Have you been traveling a lot or under stress from work or school?
Two of my girlfriends went to study abroad for a few months on the other side of the world. They didn't start their period for 6 months after coming back home.
I know I've skipped a few periods because of lack of sleep during midterms/finals week or times when personal issues became very overwhelming.
You have to look at your situation and see what's going on. Talking to the doctor will definitely reassure you. S/he can see if it is only stress or something serious.

stress can cause you to miss a period, exercise (like obsessive) can cause that, low in some minerals and/or vitamins like iron, calcium, potassium, B. have your doctor run a blood test. you can be low on some things and not even know it. even if you take a multi vitamin every day you wont get enough of any of the above minerals. no multi has enough iron or B and especially not enough calcium.

study nutrtion for 10 years

missed period, late period and.or irregular periods have several reasons - you can check - see link

http://www.women-health-info.com/252-MEN…

It could be due to stress!