I have a tumor..

A fue weeks ago a did a post called "I may or may not have lymphedema". A lot of people said "Get checked, it's probably nothing, you a very young.."
Well I started checking it out with doctors, and it turns out it's a tumor, it's also quite big and located in a dangerous zone, in worst case scenario, I may have to get my arm amputated....
I have been crying none stop, trying my best to live life as normal as I can, trying to convince myself it might not be cancer, it might not be a bad tumor...
But it getting harder and harder, I just fear the worst, living life with almost to mo care in the world, all of a sudden I am in danger of dying and losing an arm.
Biopsy hasn't been done yet, I have to wait for that to be sure if it's a bad tumor or not... But the fear for the worst is eating me alive. I can barely eat, I have never been someone who eat much but since all this started I noticed I eat maybe one or half a meal per day, I can't enjoy things I use to, movies, videogames or going out with friends because all I can think about is 'Cancer, Cancer, you might die on a terrible way soon, you might get an arm amputated, what are you gonna do? You might suffer terribly"
I feel like I am in a constant state of dream, like none of this is real. It's all going by so fast but at the same time I just wanna come out at the other side as soon as possible, get it over with and be done, with two or one arm.. just get it over with as soon as possible. But I also wanna stop time, and have nothing change, make everything stay the way they are now. Everyone saying I can lean on them, and I don't even know if I want to. Sometimes I wonder if seeing a particular friend might help, or spending a night at a friend's house might help take my mind of things, at least for a while... But god I am so terrified of everything.