i'm sure others have told you this... but there was probably already a problem when she jumped, or she wouldn't have 'landed wrong'.
we always blame ourselves for things like this, even when they were not preventable... i know i did, when Mouse died. i kept going over & over what i could've done differently... if i had taken her to the last vet, first, or noticed a problem earlier. my head knows differently, but my heart still said/says those things.
it's so difficult when they leave us, even with warning, but i think the sudden, unexplained passings are harder. i've had both, & i really felt worse when Mouse died, within only 10 days, than when Medley passed, after about 6 weeks of illness.
you did what you could, & you couldn't have known that her jumping off the bed would suddenly be a problem, when it never was before