Welcome to Tom's Hardware, @Beadingterri!
I'd recommend you try using a different USB cable with your external drive and also attempt to connect it to another computer to see how it will get recognized there. If the cable cord is very loose, it's most likely damaged. If changing the cable doesn't help, you should definitely get in touch with the reseller's/manufacturer's customer support. Since the external HDD is relatively new, you should be able to RMA it and get a replacement from them. However, make sure you do a backup of all the data you have on it beforehand, otherwise you won't get it back with the replacement drive.
Good luck!
SuperSoph_WD