Hello. I'm sorry you're having problems. There are several issues to address here:
First, your history of menstrual irregularity is suggestive of
polycystic ovary syndrome (PCOS), which is a
hormonal disorder that interferes with ovulation, disrupts your menstrual cycles, and often leads to excess hair growth,
infertility, stubborn acne and weight gain. Physicians frequently use birth control pills to treat (PCOS), as this cycles the lining of your uterus, prevents infrequent, painful periods, and reduces your risk for
uterine cancer.
Second, birth control pills will regulate your cycles while you're taking them, but as soon as you stop taking the pills you're likely to go back to your previous menstrual pattern, which in your case was apparently quite irregular. Given your negative
pregnancy test, missing those two periods after September was due to your underlying irregularity, not pregnancy.
Third, I presume the hospital doctor performed a few tests before he/she prescribed
Regestrone. He probably made sure you didn't have a
pulmonary embolism (a blood clot in your lung), and I suspect he ordered another pregnancy test to make sure you weren't pregnant -- even though your home pregnancy test already proved that you aren't pregnant. The Regestrone was then prescribed to trigger menses and restart your menstrual cycle.
I can understand your concerns. However, it does not sound like you're pregnant, and it would be advisable to proceed with the treatment prescribed at the hospital. You should then see your personal physician to determine whether you have polycystic ovary syndrome and discuss how to deal with this condition.
My best to you.