Hello, and I hope I can help you today. Pregnancy symptoms vary widely between women, and many of the same symptoms people associate with pregnancy can also be caused by other hormonal factors associated with missing your period. Thyroid disease, diabetes, weight gain or loss, stress and other factors can cause you to have irregular periods. So, if you are having unprotected sex and are at risk for pregnancy, but your test is negative, then examination by a gynecologist would be prudent to rule out any other causes of your irregular cycle. I hope I was able to adequately answer your question today and that my advice was helpful. Best wishes, Dr. Brown