Sounds like one of your Buds maybe cross threaded your shaft for you.
Here is a tip. When screwing a shaft on, and this is very important with a
pin to wood joint, start the turn by turning the pin to the left instead of the right. You will feel the threads just slip or for a better word, drop into into place. Then start to turn the butt to the right. This will help in not cross threading the joint.
You should be ok as long as you can screw the shaft on and tighten it up without it becoming loose during play.
In the worst case scenario, a repairman can plug the shaft, bore and tap it
for your pin again. All is not lost. And its not the most expensive repair job in the world either.
Something that you also might try if you find that it is hard to screw your shaft on. Do the steps that I mentioned until you feel the threads drop in. Screw the shaft on a couple of turns. Then, gently apply bit of opposite force. Your shaft and your butt, with your left and right hand, apply a bit of opposite outward and backwards pressure, while still screwing the cue together.
And lastly, try and not lend your equipment out to Bone Heads any more. Unless they are willing to pay for damages.