Problems of the thyroid gland, pituitary gland, adrenal glands, or ovaries can be rare causes of irregular periods. A positive pregnancy test is the only way to be certain of pregnancy. It is best to see your doctor for a pregnancy test because home test kits can be confusing and give misleading results. In addition, it's important to have a supportive person available to answer all your questions if you are pregnant. Breast swelling, weight gain, and nausea are additional signs of pregnancy.
Some stress is a normal part of daily life.
Only you can know if you are under too much stress. If your doctor finds nothing abnormal during your physical exam and you've been having periods for 2 years or less, your irregular periods may be part of your normal development. Remember, if you have had sex, go to your doctor's office for a pregnancy test when your period is late for you, even if you normally have irregular cycles. Also, if you are having sex, read the information on birth control or discuss it with your health care provider. If you have missed several periods without an explanation, your doctor can check your ovaries and look for any signs of hormone imbalance.