Is This Normal?

I’m 15 and i’ve had my period for over 2 years now. My cycle typically lasts anywhere between 42-46 days (though i’ve had cycles go from 31 days and then suddenly 61 before), and my actual period lasts about 11 days. Over the past couple months my period has gotten heavier and heavier; bleeding through pantyliners, plus sized tampons and my pants within a couple hours. And the back pain is awful. I cramp really bad, but it’s the lower back pain that gets me. I’m mostly sure this is all normal, and it probably has to do with me being a young teen, but I would only like some clarification. :)