Please help with advice!!

Becky

So I haven't had my period since January. Ive took multiple pregnancy tests & all come out negative. I haven't been to a doctor because my mom is very strict and I'm not comfortable talking to her about it, I am only 17. I've always had a regular period just maybe a couple days late. I've heard if you don't have your period for a while like what is happening to me it could mean you're infertile?

Please help on what I should do!