How do these noises sound like? I'd recommend you to check this article about the different sound failures and what they'd potentially indicate: http://datacent.com/hard_drive_sounds.php
I'd also strongly advise you to back up all your school work right away somewhere else before proceeding with the troubleshooting!
Then go to your external HDD manufacturer and download their diagnostic tool to test its health and SMART data. It won't hurt to check the warranty as well, if it's still covered, you should be able to RMA it and get a replacement from their customer support.