Is this Paranoia? Is this an anxiety disorder? Please?

I have always overreacted to the simplest of things...like if I see something unusual on my body I automatically think it is cancer or I am going too die and I have a panic attack and have to be reassured that I am fine only by a doctor or I will like stay up and won't sleep and think about it until it is resolved...is this a disorder or paranoia? Do I need help? I am 13 and have always been like this...Is this just me overreacting or is this a disorder? I am not a dramatic person about other things but I always think something is wrong with me...? Please no rude answers and Thanks :)