Yes. Yes. Yes. To all you said. It's really a jolt when you are given the news. I empathize. It's really very much to process. You identified the key thoughts + feelings. It's a heavy load.
I will encourage you with the knowledge that you do begin to absorb it and get a better controlled perspective with a little time and information. Feels less turbulent and less out of control then.
It's my view that asking your Dr for low dose short term anti- anxiety medication is OK. This is a major emotional and life crisis for you. You might also ask about a short low dose course of steroids if it would help your symptoms temporarily as you navigate your medical journey.
No one knows the future. There's a justified place for hopeful expectations and optimism within the unknown and scary. Always remember that in the storm.
And remember that you are still the one making the decisions as to treatment. You have time. You have options. Take a deep breath now and then and let the earthquake underway quiet down a little. If you have a faith, go to that well. You are not alone. Your future is still unwritten. Hold steady in today. And keep in touch.