Sending soft hugs, Mamanan. I think we've all been there in one form or another, fearing our multiple illnesses, pain, uncertainty, and the future. We do understand and care here.
Try to take one minute at a time; one day at a time often seems like too much, but one minute at a time is manageable. Take a deep breath and try to focus on just the here and now and not worry about what will happen tomorrow. It might be a good idea to talk to your priest, as you mentioned. Maybe he can help you get some emotional relief. God is a big God. He can handle your fears, uncertainty, anger, and doubt.
One of my favorite quotes by Mark Twain: "I am an old man and have known a great many troubles, but most of them never happened." This quote probably helps me cope about as well as anything. It really helps me not to be anxious about what might happen.
Just a personal experience: I have TMJ and thought that I was having a horrible flare recently. I had the same problem last Christmas. It turns out the the recurring awful pain in my jaw, ear, head, neck, and mouth was from a tooth that needed a root canal. I had the root canal, and the pain "mysteriously" went away. Since I do have TMJ problems, I would have sworn on my life that it was causing the pain, but it did turn out to be a tooth problem.
I think it is often really difficult to pinpoint the cause of head, mouth, and neck pain. Hopefully, you will be able to get a good diagnosis and treatment.
Soft hugs - Austen
"There is no charm equal to tenderness of heart." - Jane Austen