i have a question ...can any one answer

I had a regular period for years and then i found out i had a cyst after having excessive bleeding and bad cramping for about a week. I was on birth control and usually birth control is supposed to prevent cyst or prevent them from forming(im not sure).We monitored the cyst for a few months to make sure it wasnt growing... it wasnt so we didnt need to look into removing it. Shortly after i stoped having my period and its been over a year now and i still do not have a period. I am 17. and i have asked my doctor if anything was wrong and they never have really done anything about it! They have never ran test or anything pretty much just ignored it. My mother say its noraml to not have a period but it worries me and i was wondering if not having a period could prevent me from being able to have children in the future. ... Or any kind of response to my problem!!^^