Okay, so I need help, fellow Coroll-ers;
I think I might have a bent axle, though I can't be too sure.
The story goes as follows:
I had just bought a set of wheels from someone on craigslist (bought a pair of grey tom's igetas from a really nice guy for 250$ a set. didn't know what they were when i got them; i was just looking for tires lol.)
anyways, i pulled into my garage which is usually a living area, but had enough room for my corolla. the floor is carpeted*.
me and my cousin jack my car up to where the tire is a good inch or two off the ground, and begin to unbolt my current wheels.
the front driver's side wheel first, we get the wheel off and are about halfway done putting the bolt adapters needed to put the tom's on.
the car moves back a bit, and the car falls from atop the jack.
when my cousin parked my car, he didn't put the e-brake on. the car fell off the jack and landed flat on the rotor. there was no visible damage, though, and the fall itself was kinda graceful. we got all the wheels on, and when i drove it, i heard a knocking noise. subtle at first, but then it got louder and louder, til now, it's very unsettling to hear, and it rocks the whole car.
tl;dr- my car fell from the jack stand approximately 8 inches and hit a carpeted floor with the rotor. now there's a knocking noise.
what could be wrong? is it a bent axle? someone said it could be the dustguard bent? torn boot? godzilla attack?
if anyone knows what I'm talking about, i'd appreciate some help. school's monday, and i hate busses.

i'd also appreciate help on fixing said problem?