This time when the options pull up, choose 'Restore from Time Machine Backup'. Reboot and go into recovery mode again (press cmd + r during reboot). Even if you're convinced you don't have one, it doesn't hurt to give this a shot. Try restoring from Time Machine Backups (you might actually have one) - I cannot emphasize how strongly I believed I didn't have one of these backups, but unbeknownst to me, it did exist on my drive.After an agonizing 30-40 minutes, it'll give you the same error - 'not enough free space to install the OS'. Once you do so, and assuming you're connected to Wifi, your macbook will start downloading Mojave and eventually attempt to install it. Don't worry, you won't loose your data doing this as it merely overwrites the OS, it doesn't overwrite your files. Once there, I clicked on 'Reinstall macOS'. Since I couldn't boot from 'Macintosh HD' anymore (I was just getting a white circle with a bar across it), I rebooted my macbook and pressed Cmd + r. Try to reinstall Mojave (this won't wipe your disk) - I wanted to return my macbook to as original a condition as possible, and I figured attempting to install Mojave was the best way to do it.I'm not sure if step 1 was necessary, but since I did this en route to fixing the loop of death, I'll list it here for you to consider. I was facing the same issue and was on the verge of reformatting my macbook.

How to free space on macbook pro