Computer crashes on login, greeted with flashing folder icon So here's what happened
I was happily using my Macbook as usual, and I closed the lid like I always do when I put it away.
When I came back and wanted to use it again two hours later, I open it up and type in my password. Strangely I'm greeted with the infamous spinning beach ball of death, and after a minute or two of the computer not responding I close the lid again.
I then hear the boot sound, and thinking the computer simply crashed and rebooted I open the lid, only to see the flashing question mark folder.
Doing some research I find that it means the computer can't find the boot drive, so I reboot into Internet recovery mode, and try to select the boot drive... Nothing's there. I then go to Disk Utility to try and see if I can repair the drive. All I find is the base system, to which I don't have write permissions, and as such am not allowed to repair or format.
What do I do? I don't want to lose all the precious work I have on it, and I don't have a time machine for backups.
It's a late 2011 13 inch Macbook pro with 8 gb ram and a 2 tb hard drive
New Information:
The computer boots fine from the hard drive if I connect it via USB, so I suspect it might have something to do with the cable, but I'm not sure.
It may be as simple as the cable has become loose.  If that is the case, it is a fairly easy fix.  Sorry to see you don’t have a backup.  If the drive has gone bad, that would have been your recourse.

For future reference, a simple external drive connected via USB will work fine as a Time Machine backup disk.  Even if you are not as regular in connecting it as you should, you would at least have a backup in case of catastrophic failure.  There are other online backup solutions too that are subscription based.

If you are comfortable with taking the MacBook apart, you can check the cables first.