Hi chaps, I'm not having much luck recently

A few days a go we had a good covering of snow, which of course has exposed quite few pot holes!!
I've driven out a few times since it's snowed but not hit any of the holes unduly hard?
When out in the car today I noticed the steering wheel was off centre when going in a straight line?
If not the pot holes, could anyone suggest a cause of this please. When I let go of the wheel it doesn't pull to the left or right, just straight as normal, but it's off centre?
Any ideas please?
Regards,
Mart