Girls, Haven't had period in months?

So this is kind of awkward but I'm sixteen and I tend to have long periods of time where I don't get my period. I haven't had it since at least late January and I'm kind of panicking. I'm not sexually active and I don't see any reason there could be a problem.
I work out quite a lot and my BMI is 18.5, would that have anything to do with my health?
Thanks in advance
Updates
+1 y
As many opinions as possible please. And what you think might be the problem?
Girls, Haven't had period in months?
Post Opinion