I have not felt well for 12 weeks. I also haven’t had my period in 4 months. It hasnt regulated yet but its is still a long time not to have it. please help thanks!

Adolescents typically have irregular menstrual cycles and it may take years before it becomes regular. A lack of period for four months is suspicious for pregnancy and you should take an over the counter pregnancy test. However, if you have never been sexually active you should be evaluated by your primary care physician for a physical exam and laboratory tests.