Why do i worry so much about everything?

I have this problem where I worry about everything too much, mostly about diseases and death. Like an hour ago, I thought i had testicular cancer, turns out that I don't. Then a few days ago I swallowed my bracket from braces and was freaking out because it was harder to breathe and found it was only just inside my head. Another example is my gums started hurting and I thought I had gingivitis so I told my dad to hurry and schedule an appointment. Whats wrong with me? Do i need to seek a psychiatrist? I am currently 13 years old.