The condition you have is known as secondary amenorrhea, and I suggest you schedule an appointment with an OB/GYN.. This is when a woman's period stops coming along as normal time after time of having normal periods. I think you knew there are three possibilities. The first one is that you were pregnant and the pregnancy test you took resulted in a false negative. I would probably say that this is the least likely of all the possibilities as home pregnancy tests are fairly accurate. Another possibility is that you have developed polycystic ovarian syndrome. This is a condition that results in hormonal imbalances and often results in the ovaries not ovulating. This can result in very irregular periods and subsequently women can go multiple months without bleeding
at all. This condition is also associated with weight gain, diabetes, high blood pressure
, and sometimes abnormal hair growth on the face called hirsutism. Another possibility is that you have stopped having your period due to weight loss
. Women that exercise vigorously and/or lose a lot of weight quickly are at risk for losing their period. The treatment for this condition is to tone down the exercise and perhaps can't slight amount of weight back if you have lost weight recently. Again, I suggest you schedule an appointment with an OB/GYN. This is the type of position they can most easily address this problem.