Not Sure If I Should Be Worried..?

I'm 17 and I didn't have a period in the year of 2015 save for maybe one in January and then one right on Christmas day. 2016 rolls around and I skip January and February. Now it's March and my flow is incredibly heavy and I'm more than a bit worried.

I usually use S+ and I can make it a whole school day without changing it. But for 2 whole days now I've been bleeding so much that I go through a S+ in 2 hours or even less! And it hasn't let up even a little! Usually by now it would kinda calm down and I would be able to survive but, couple this with severe lower back and pelvic pain and the occasional migraine, I'm thinking this could be more than just a period?

I'm thinking about going to a doctor and maybe asking if using birth control can regulate me and possibly lighten some of this burden.. Think this is a good idea or am I just overreacting?