Do you have that USB drive backed up anywhere?
We often have lost USBs handed in at the Library, but we also have many people come and ask us for USBs that haven't been handed in.
USB drives are easy to lose. They are also easy to leave in your pocket when you put your clothes in the wash. And they can develop faults that make the data irretrievable.
Having all of your stuff saved on one USB drive is just not a smart move.
Having all of your stuff saved on one computer is also pretty dangerous.
It's a great idea to have more than one copy of anything important - especially around assignment time.
As you are working on your assignments, save your work regularly to your USB drive, and remember to occasionally save a copy to your DropBox, Google Drive or OneDrive - or, at the very least, email a copy of it to yourself.
Regularly save copies of all of your important files to your computer, another USB drive or to the cloud.
Remember the LOCKSS principle:
Lots Of Copies Keeps Stuff Safe