No period for 6 weeks?

I’m 14 and got my period around 6 months ago and I don’t know why I’m not getting my period I’m not sure if it’s just regulating and not in a constant cycle yet or it could be because I’m vegan should probably be supplementing. My mom doesn’t want me to supplement because she thinks I should just get B12, iron, D, etc... from foods and not take vitamins. I normally have a heavy period that lasts a week and than I’ll have two weeks off my period for it to start again. I’m just confused and don’t like talking to my mom because she doesn’t like to talk about my health and she thinks I’m a hypochondriac.