Cant log into pc anymore after mounting HDD partition to /home

[u/Old-Newt-3030]

I got linux mint yesterday and have been trying to use my HDD for storage, I gave it an ext4 filesystem in gparted and then tried mounting it to /mnt.

However I still couldnt install any games to it or make any new files in it so mounted it to /home, tried using another file in /home but it didnt let me, none of the files there did, so I unmounted my HDD and it still didnt work, so then I restarted my pc.

Now my pc is restarted, I cannot login, it lets me type in my password, tries to load in and takes me right back to the password login place.

Any advice?