It is ridiculously unlikely a 13 year old develop a brain tumor. I promise you, you're experiencing anxiety. All your symptoms are consistent with anxiety. Headaches, no matter how rarely you have them, are not a pathological indication of a brain tumor by themselves or coupled with the paresthesias you've mentioned. If it were a brain tumor you would KNOW something were wrong. You would not be suspicious or consulting an anxiety forum. I will repeat, you do NOT have a brain tumor. Everyone here knows exactly how you're feeling. You do need support and shouldn't feel guilty. I have been in your shoes. My health anxiety began when I was 8. I'm now 22. You are okay.