Hello, and i hope I can help you today. Pregnancy symptoms vary widely between women, and nausea, mood changes, breast tenderness, cravings and bloating can occur from hormone fluctuations that occur during an irregular period as well as pregnancy. You may not be under much stress, but even worrying about getting pregnant can be enough to delay your cycle. So if your pregnancy test is negative, your late period may be just a chance occurrence and I recommend just waiting until your next one is due and see what happens. You may just get another cycle (be prepared though, you will probably bleed more heavily as there will be more tissue in your uterus due to not getting your period the month before. If you miss your period for more than three months, you should see a GYN doctor for a hormonal evaluation as there are medical problems, such as thyroid disease, that you should be screened for. In addition, the doctor can prescribe medicine to help make your period come and hopefully reset your cycle. I hope I was able to adequately answer your question today and that this information was helpful. Best wishes, Dr. Brown