My Book 6TB

My Book 6TB WD external hard drive was set up and a ton of information was prepared and loaded onto it Oct 9, 2019. When I tried to look at the information on the hard drive there was no icon on the desktop and no hard drive shows in the list of drives on the computer. I am using a MacBook Pro. Does anyone have an idea for me? When I plug the USB into the “C” adapter for the computer the fan on the external drive is easy to hear but nothing shows on the computer. If I cannot recognize the drive then I can’t access the files and the backup is worthless. A ton of time was spent organizing this information and I could see that it was loaded on the drive after I was done. I can’t understand how I can just have a dysfunctional drive after one backup. Please advise ASAP I am panicked.