We (Bav 36 2004 1.8M draft) touched the bottom for a few seconds over the weekend attempting to find calmer water. I would guess the bottom was rocky by the sound (which I dont want to hear again :-( ). All is dry and looks as normal but would welcome any advice/experiences before we succumb to the obvious and lift her out for a look.
It sounds like you just bumped up and down a bit. It's probably fine. They're pretty tough old beasts.
You have to hit the bottom hard enough to knock you off your feet before you're likely to do any damage.
It doesn't sound like you hit hard enough to do major damage. If that were the rudder you may be singing a different tune. it may be easier and cheaper to ask a diver to have a peak...especially if they are a friend. Unless you can put on a mask and take a look yourself for a piece of mind. Good luck either way.