Unable to Log back to RHEL 8 using admin password

I beg for help. new to this. My root partition was @100% full, I tried to extend it when I restarted linux pc I got an emergency message. I entered root_user/root_password. I was able to log into machine, and went to edit /etc/fstab folder. I put a comment # on line #/dev/mapper/rhel-home, rebooted and was allowed to see my loging screen. I entered my admin password, but it is not working. I logged in as root using root password. once inside I am unbale to switch to /home/admin_user, it says I have no access. I am super stuck. I need to log in as admin so I can practice my oracle classes. I am needing help so bad. Please help.

RHL 8 on a dual boot. Windows working fine only linux. Please a step by step help will be very appreciated
* Admin_user/Admin_password not working.