Locks at startup, can't pull data, hard drive fail?

I've surfed the forums for several days and found similar threads that were helpful in trying to diagnose, but nothing specific to my problem. I apologize if it's a repeat.

My MacBook pro (less than a year old, Yosemite system) slid off my desk the other day. It seemed like an average fall, hit the floor on the bottom right corner (hard drive corner) but it didn't seem like that hard of a hit. It was ok when I picked it up and ran fine initially. My past macbooks have taken tumbles before, far worse than this, and none have had any issues so I didn't think it would be a problem. After a few hours of average use it locked up while running safari. No response to force quit so I did a hard shutdown. Upon restarting, it came up with my login as usual, then the status bar as usual, but the status bar froze about half way in, eventually requiring a hard shutdown. Tried it several more times with the same result. Even deliberately typed the wrong password in my login and it recognized that it was wrong. Tried starting in guest mode and safari ran fine but of course nothing else is accessible anyway. Tried booting in safe mode and it froze at the status bar again. Tried starting in recovery mode and it recognized the drive but stalled while trying to verify permissions. Tried starting in diagnostic mode and it stalled after checking memory. Tried resetting the pram/nvram and SMC with no change. Pulled the bottom off and visually inspected the hardware with no obvious damage that I could see, disconnected and reconnected the hard drive cable with no change. Successfully booted MacBook in target mode to try accessing my data from a desktop (mac mini) trying both FireWire and Lightning cables, the box would come up on the Mini to enter my password for the MacBook but when I entered it would stall for a while then shake as if it was the incorrect password, tried running recovery and diagnostics from the desktop and it didn't even show the drive. Tried installing an old drive that a coworker had laying around out of an older MacBook but it just booted to a question mark, so I'm not sure if it's the wrong drive, no system, another damaged drive, or a different damaged component on my MacBook. He didn't know either since he has random hardware laying around from every computer he's ever owned.

Is there anything else I can do to diagnose the MacBook for sure? My assumption is that the drive was damaged in the fall but I'm not inclined enough to say for sure that it isn't the hard drive cable, motherboard or even just corrupted data that had nothing to do with the fall. I'd prefer not to take it to an apple tech unless I know the data is gone as I have confidential healthcare information on the drive and can't risk it being seen. I could try erasing the original drive and reinstalling the system next, but I'd hate to lose all of my settings if I don't have to even though the really important data is redundant on other computers. I'm not even sure that it's possible if it can't communicate with the hard drive as it is.

Any suggestions would be greatly appreciated.