I am afraid of getting brain cancer...

I'm 15 years old, and I've had anxiety problems all my life. Just this summer, I started getting bad panic attacks, especially while away on vacation. Once back at home, I felt better, and just experienced my first panic attack in two weeks yesterday. I got a bad headache and took some ibruprofen for it, which usually works wonders, but it didn't work this time. I am terrified that the sort of full, pressure feeling in my head means brain cancer. I am trying not to freak out, but do you know if this could mean anything? Is it just my anxiety making up fear, or should I be concerned?
Thank you so, so much.
-Elizabeth