Hello Papa and welcome to the site.
There isn't a happy medium between hypochondria and mindfulness is there, although two people in a relationship sharing those qualities will balance each other out.
So for the time being you'll have to wait it out, but by being on here you do at least have folk who listen and to whom you can talk, whether you have Prostate Cancer or not.
Did your GP do a test of your urine to rule out infection? If not go back and ask for one.
PSA of 5.6 isn't massively high but then does show something needs investigating, as does a large prostate.
I don't understand either why checking out the PCa should be put on hold for the time being due to your back. Perhaps somebody else will point out why testing is currently on hold. Unless the GP is saying the stress of the back is raising the PSA and giving a false reading, as would an infection.
If indeed it is an infection he would surely need to be giving you antibiotics?
Post away on any fears you may have. IF we can chat to you and help you overcome them then that's good, but I have to say that worrying about it all, when it may not be necessary, will put a dampener on the festive cheer that your wife and family will want to share.
As Chris says, try and put it to the back of your mind until such time as you can go and "bully" the GP into pulling his finger out