I am seventeen years old and i went on birth control at the begin of this year in order to control my heavy periods. The first month on my birth control, which is minastrin, my doctor said was normal, i got spotting in the middle of the month and a full, but light period on time. The second month was perfect. I had no spotting in the middle of the month and had a short light period at the end. The third month is where things got bad. During this time, i had two full periods and spotting. The first period was at the beginning of the month, i didnt really keep track of how many days, but it was longer and stronger than the spotting. In the middle of the month was spotting and at the end was the full period. This was my last full period. It was light but the blood was stringy and mucus-y. I went to the doctor after as a check up and he said that this was normal and my body needed to get used to the pill. Last month however i did not get ny period at all no spotting until the begining of this month. It was very short spotting and it happened again on sunday. But no full period today i was supposed to begin my period but nothing again. Not even any spotting. I know for a fact i am not pregnant, as i am not sexually active. I know that birth control pills are used to minipulate periods but at what point should i be concerned and call my doctor? Thank you