I made a mistake by running some commands like:
sudo chown $USER:$USER ./
rm -r ./
because I was trying to own the directory and delete some stuff. So, once I run these command lines and rebooted, I couldn't login back to my ubuntu. It feels that it wants to but then kicks me back to provide my password again! Any solution for this problem please, any around solutions?
So you removed a lot ;)
I suggest to download Ubuntu Live (download ISO file from Ubuntu site), upload it to USB stick and run it. Then check what's left in the folder you have been working with. If that was your home dir, then restore it (create it if needed) and try to reboot.
Good luck with fixing. Merry Christmas