If her anal area looks normally, this would all fit with some muscle
soreness from the ungraceful episode yesterday.
Check one more thing for me please, just to make sure this isn't an emergency. Get Zoni to standing normally and comfortably on the floor, and gently flip a rear foot over so she has to stand on the top of it, all knuckled over. Repeat this several times and observe to see if she stands on it knuckled over, or it she corrects it back to its normal position. Try it with the other rear foot too.
If she is having severe spinal problems, she won't correct her foot placement, and I would take this a lot more seriously.
If she corrects it, then continue to just allow her to rest and heal. Be careful with aspirin. It's hard to use enough to provide relief without also causing an upset stomach
. Dogs are pretty sensitive to it. If you have any prescription doggie NSAIDs on hand (carprofen, previcox
) on hand, I can help you figure out a dose for her.