I'm a week late for having my period, I read about how stress and life changes can totally mess your cycle up.. but I'm not sure.. I was on the road with my b/f the last time I had my period. It was a normal period for me and everything. I'm careful most the time to use a condom, and not have sex 2 weeks afterwards because I was told that's when a majority of woman ovulate.(correct me if I'm wrong though! ) But now, I'm a week late. I am no longer going on the road, so therefore my diet has changed, and I'm getting more exercise. My brothers wedding was also going on the week after I got off the truck, and I was pretty stressed for them 2 weeks. And not knowing that I might be pregnant, I went out drinking about 2 times a week in the past month, and not to sound like an immature little college girl, but I did drink quite a bit, and was taking excedrin for the lovely headaches afterwards. So hopefully, I am not pregnant, and if I am I hope that the baby will be okay! Oh, I also took 2 of them digital at hpt and they both said Not Pregnant. I did them both a day apart, one on the 5th day of missed period, and one on the 7th day.

Home pregnancy tests can give a false negative so if you had unprotected sex during the last month then there is a chance you could be pregnant. I'm sure you have a health center on campus and they can perform a more thorough blood test or do a pelvic exam.

Natural Family Planning/Birth Control (which is what you are doing with not having sex 2 weeks after your period)... is only effective if you chart your cycle, BBT, cervical changes etc. And even then, it is not the most reliable form of birth control.

A woman can ovulate at anytime, while it is likely they won't ovulate until about day 11-15, it is still possible for your to ovulate anytime during your cycle. So not having sex the 2 weeks following your period is definitely not practicing safe sex.

The change in your daily routine is most likely the cause in the change in your cycle. Women build up HCG at different levels, so it may be too early to register positive on a HPT. HCG doubles every two days, so I would wait and test again in 2-4 days. If it is still negative, and you still haven't had your period, I would set an appt and get a blood test done just to ease your mind.