Welcome to the club you never asked to join, Mike!
I hope it won't be long before your test results allow your specialist doctor to plan your treatment if needed and get you out of that limbo-land.
As for whether carrying a post bag will make things worse, my doctor told me right at the beginning after diagnosis (after some of my vertebrae collapsed) not to lift anything heavier than a handbag!
So I would speak to your supervisor immediately about getting a trolley or frame on wheels to take the load off your spine.
Some of our posties have one like this
[img]http://news.bbcimg.co.uk/media/images/59571000/jpg/_59571574_59571573.jpg[/img]
and I have seen one local postwoman actually jogging with hers!!
Since my SCT in August 2010 I have been receiving monthly infusions of a "bone strengthener" called Zoledronate, which seems to have stopped any futher deterioration of my spine, so hopefully they will be able to stop any further damage.
Love
Eliz
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