I am seven days late for my period. I usually have regular on times, I recently started working, it is a pretty physical job lifting and what not. I have been getting about four hours of sleep lately.(because of work). I have a 5 year old and a 9 month old already. My husband and I are not trying or anything. I am wondering, the reason I have not started is from lack of sleep or changing my routine from working. I also took 2 pregnancy tests and both negative. HELP!!

Stress can play a wonderful factor in women's cycles going screwy, a major change in your routine will make your body confused if you are having unprotected sex then yes that's a pretty obvious probability but if the test says no then id go have the dr check you out to be sure.
Good luck and try and calm down lots of hugs xx