Mac Mini - No Ethernet Interface

Hi,

I have Mac Mini 2011 model, and I have been using it with ethernet connection for quite a while, haven't had any problems, connection worked perfectly till now. First there was no internet connection, so i just connected to wifi for a bit, then i went into System Preferences - Network, where over ethernet it indicated "cable unplugged" even though the cable was plugged in. I checked the cable is not the issue, works on other devices. Then I though if i just delete the ethernet interface with - button and then add it again with the + button that would solve the issue. However, now ethernet interface doesn't even come up as an option:

I am currently running OS X El Capitan 10.11.3.

Please help resolving this annoying issue, because the ethernet port is key for the speeds for me.

Thanks in advance!