It's staggering how quickly you go from perfectly OK to constantly wondering about everything, panicking and becoming best friends with a pack of medical persons! All the above is practical and really useful. My suggestions are: don't overthink stuff - half of what may keep you awake at night may never happen. You will discover you can do stuff you never thought possible. To be fair, you may not really want to do any of it but take pride in the fact that you will rise to the occasion. Keep your eyes on the prize, getting rid of cancer, all the rest is just a means to an end and will pass. I found keeping busy (like @kezmusc I worked through treatment) didn't leave too much room to fret unnecessarily. But if you can't, occupy your mind as much as possible. And take every and any opportunity to make this experience work in some way for you - it's possible, hard work but it helps keep you focussed on moving forward. Looking back at what was is fine if you are going backwards, but you are not. Very best wishes.