Not Savings/Vanishing Buildings

Yesterday after playing for several hours and exiting/reentering the game with no problems, I was suddenly spawned to a new location and could not find my buildings anymore.
Today, after making a new world last night, the game loaded to the exact location, but none of the things that I had built were there.

Despite saving multiple times by resting in a bed, all of what I had done is gone.
So to test it, I booted a new game, played for a while, saved multiple times (this time in a tent). The game crashed, so I reopened, and, of course, none of my buildings are there either. I checked all of my load files, and could not find my buildings in any of them. :C

Very disappointing.
I thought that the first issue I had was simply that I had been spawned to a completely random location, away from my buildings, but now that this problem has presented itself, I'm thinking that it just stopped saving.
I am playing Creative on a Mac, and my game is installed through Steam.
I had been playing the game all day yesterday with no problems until several hours later. It had saved fine and allowed me to enter/exit the game without any issue.
Also: My inventory has been full of the things I had crafted/found during the time I was playing, including the items and quantity that were used to create the buildings which are missing...

Not sure why it's suddenly not saving anything...Please help!
Thank you!

Quote from red51

I'm sorry to hear about that Eventually there may be something which prevents the game from writing to the hard drive properly.. Do you have any antivirus or security software installed on your Mac? If so, what programs do you use exactly?
You said a crash occurred (it's not the reason why the buildings aren't saved, since the game does usually save the world every 10 seconds), what happened exactly? Did you get an error message? Or just a crash to desktop without any information? Please have a look if there is a file called "errorlog" or "hs_err_pid" in your game directory (to get there, rightclick on rw in steam -> properties -> local files -> browse local files), if there is such a file, please upload it here

It's okay. It's encouraging my creativity, at least, haha, rather than me getting stuck on one build. :]
And yeah, I crash occurred this time, but the problem started before the crash, so I don't think that's what did it... There was no error message or anything, the game stuttered a bit, then froze, and then just closed without warning. I have no antivirus or security installed, and I did not see any file suggesting anything to with error in my game's directory.

I've been playing the game since the original post on this thread and it hasn't crashed yet. I've been sleeping in the little starter tent, then quitting the game immediately after each save and reloading, and so far everything has been where it should be. Not sure... I'll keep you posted if anything else happens.

Quote from Miwarre

Just for clarity: sleeping is not supposed to save your work, this happens automatically every few seconds (as @red51 said). Sleeping only sets your re-spawn point.

Yes, but I thought that by sleeping it would encourage the game to absolutely spawn me to that point, just in case anything goes wrong.