Hello, and i hope I can help you today. Pregnancy symptoms vary widely between women, and nausea, mood changes, breast tenderness, spotting, cravings and bloating can occur from hormone fluctuations that occur during an irregular period as well as pregnancy. Your period can be affected by stress, weight changes, travel and even worrying about getting pregnant. Furthermore, the most common sign of pregnancy is a missed menstrual period, so if you are not yet late for your period, there is no reason to suspect that you are pregnant. However, if you are having unprotected sex and do not get a real period at the usual time for you, I would perform a urine pregnancy test according to the package directions. If you are not pregnant, then you most likely just had an irregular menstrual cycle. If you miss your period for more than 3 months, and your pregnancy test is negative, you should consider seeing a GYN doctor for a hormonal evaluation and to rule out any medical problems, such as thyroid disease, that can affect your cycle. I hope I was able to adequately answer your question today and that this information was helpful. Best wishes, Dr. Brown