Problems connecting via ethernet

I have a late 2013 MacBook Pro running El Capitan. Recently I bought a USB-to-Ethernet connector so that I could connect to Ethernet. It was working fine, but now it's not after a few days. I don't see the Ethernet option under "Network Preferences", and I tried resetting my PRAM (as I've seen on some other suggestions here) but that didn't work. Any clue as to how I should proceed?