Terminal behaving suspeciously with error dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem

I was trying to install the Realtek 8111e/8168 Driver on Ubuntu.Using this command:

sudo apt-get install r8168-dkms

It didn't gave any error. But I later I wanted to delete it using the command:

sudo apt-get remove --purge r8168-dkms

This gave me an error and the terminal showed me this:Terminal Error

Now, whenever I try to run the command sudo apt followed by any other command. For example:

sudo apt install default-jdk

I am getting error:

E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem

How to remove this error without losing any data from my system?

Also, is there any way to make my linux Ubuntu system optimal as I suspect some of my commands which I followed from internet might have corrupted the system.