Stuck in the loading screen

I have been looking around and seen some people describing more or less the same issue but none of the solutions have worked for me.

Mac mini (Late 2012)

High Sierra 10.13.2

Intel Core i5-3210M

500GB HDD

4GB RAM

The issue is that my Mac wont go pass the loading screen. A few days ago App Store showed that I had two updates to be installed, a security one and an update for iTunes. I tried twice to install the security one but because of the time it would take to download I had to cancel the update both times. I did however downloaded and installed the iTunes update, which required me to restart my Mac. I turn it off and the other morning I started it, the loading bar was slower than usual, which I assume was because of the iTunes update, but once it finished, it stayed there. I left my computer on that loading screen for more than 12 hours and nothing.

I tried:

1. First Aid, but no error was found
2. Reinstall Mac (Keeping my files), but the issue remains
3. Safe Boot pressing Shift, but nothing happens.

On Disk Utility I see:

• Internal:
  1. Bootcamp 100GB (I'm writing this on Windows 10 Bootcamp, so I doubt is a failing disk)
  2. Macintosh HD 400GB (297GB free, so its not lack of space to install the update)
  3. SD Card
• Disk Images:

I have yet to erase the partition to install mac anew, but I was hoping I could fix it so I don't have to re-download everything I have. Nor I have been able to do a Restore because I don't have any backup files. I can access the partition using MacDrive and TransMac. Even though is an old computer it has less than a year of use in total because is my backup computer, which is why I doubt is a failing disk.

Thanks in advance for any reply.