I am on birth control, my period is missing for a long time

Im 24 years and I dint get my period when I turned 16 my doctor out me on birth control I than would get my period if I stopped birth control I didn't get a period was on depo shot and bleed went back to pill than stopped it since I didn't like having my period 3 years ago one month I had a natural period thinking due to maybe taking pills to enlarge my breasts than didn't receive another 2 months after that period I found out I was pregnant since I wasn't sure I could have kids after I gave birth I have been on the Nuevo ring for almost 2 years till a few month ago since I didn't like having my period and other things I thought it was affecting me now I have no period why is it I only get a period while on birth control what's wrong with me