It has been a little over 45 days since my last period. I am 18 years old and begun to have periods around the age of 10. I am sexually active however I have taken 4 pregnancy tests (2 a week and a half after my period was due and another 2 a few days ago) and they've all come back negative. I am a small person and weigh around 120 pounds. My periods are almost always regular with the exception of 1 or 2 instances. They also last for quite of few days, 6 at the most.

things i think may have contributed: - I was taking a lot of vitamin C last month (due to a cold) - I don't really eat much (maybe 2 meals a day at the most, sometimes less) - I am almost constantly stressed out about work and school