If you can swim & kayak, I doubt you've cracked a rib, unless maybe it's a small crack (just surface), & not flexed much by movement of your upper body. Hmm.
I once cracked (not broke right through) one, or just possibly two, on Mongewell Hill, off-road - & off-track into the air after clipping the inside of a rut, followed by cushioning the fall of the Aussie bloke behind me
. I wasn't sure it was cracked, rather than just bruised, until the swelling had gone down enough to feel the ridge. Front, left side, lower ribs.
It wasn't too bad when it happened. Painful, & I knew I'd done something, but my hip hurt more & worried me more (I may have cracked that - I've since had an X-ray which showed up what looked like an old, healed, crack). Got to the pub (it was shortly before lunch), had food & some liquid analgesic, then abandoned the ride & cycled home slowly & carefully.
Next morning, though . . . as Chris S described. I could hardly breathe, hardly move, & Cyclops was damn right about the difficulty of getting out of bed. Went to A&E, where they told me to take painkillers (they gave me some prescription-only NSAIDs, but only one step up from ibuprofen), & make sure I breathed fully every now & then, despite the pain. They decided I didn't have any major breaks, & weren't interested in an X-ray to find any cracks, as they said the treatment was the same for a crack or two as for severe bruising, which I definitely had*. Ease the pain, & let it heal . . .
*Among the many other bruises, there was an easily recognisable handlebar mark in an interesting place. Mrs B - then rather new to me - was most amused.