Hello. I'm Dr. Christensen.
I can understand your confusion. When you have pregnancy symptoms
, fatigue, etc.) and you've missed a period or two, it's surprising when your pregnancy test doesn't come up positive. However, there are other conditions that could account for this picture, such as ovarian cysts, pituitary dysfunction or thyroid disease. Amphetamines, such as Adderall, are a relatively common cause of nipple discharge, and they can disrupt your menstrual cycles, too. They're not likely to cause a false negative pregnancy test, though. (By the way, pregnancy tests
-- either urine or serum -- are almost always positive within two to three days after your first skipped period if you are, indeed, pregnant. And it's highly unlikely you're pregnant if you've had several negative urine tests and one negative serum test.)
Your situation warrants further investigation. I suggest you return to your gynecologist for a more thorough evaluation. He/she will probably want to perform a pelvic exam and order a few blood tests, and you could be sent for a pelvic ultrasound.
I hope that answers your question, and I hope things go well!