When I learned I had cancer, I was really scared. Scared of dying, scared of the pain I foresaw, scared of the procedures, scared of chemo. How I got through them was thinking about one thing at a time, thinking about my daughters, and how I wanted to be there as they grew up. I was still scared, all the time, but I acted the best I could. I made my appointments, I took my meds, I made sure my will etc was complete. I made peace with God. I accepted that my life was in his hands, and that however things turned out, it'd be okay.
Now I've turned the corner in my sitch. I don't know exactly what I'm supposed to do (HA!), but I know that I'll be okay in the end. I'm planning a bunch of home improvements that I want that would never have passed the wife's approval. I've bought two kittens when she hates cats, and I've always acquiesced to her over this.
Look back in your life at the tough, tough, times. Find strength in them, use them as a lever to move yourself. If you can't remember any good examples, make one now!