I nearly fell off my chair reading this heading!!!
I'm glad your darling is OK.
Years ago, I was living in an appartment on the 4th floor (5, depending on the way you count them)
I had a young persian that went missing
We found her in a corner off the garage in between the buildings. She was later diagnosed with a broken pelvis.
Under my kitchen window, there was this little concrete ledge. We guess she had landed there, had wanted to go back and had fallen, but of course we never knew.
The first vet said : leave her in a box for 3 months (3!!!!) I could not believe my ears. He said we could go to another vet that did X-rays, so we did, and it appeared the pelvis was broken not splintered. He said, leave it be.
Two days later, she ran and jumped!!! Strong creatures, cats!!
Your cat will be OK, hugs for you now, you must have been just too scared!