I don't understand how I'm suddenly using so much of my "quota space." I've been using this email for the past 3 years and have deleted tons of stuff to try to come to compliance, yet the percentage hasn't changed a bit. Is it possible I have one extremely large email that's doing this?
In webmail, you can click on the "Manage Folders" link at the bottom of your folders to see how many messages and how much space each folder is using. Then you can click on individual folders and sort the emails by Size (click on the "Size" in the headers to sort by size) and see if there are any individual messages that are particularly large.