There is an option to export an .aia file from the Project List.
If you succeed with that, you should be able to open the .aia file with free utilities like 7zip to clean out bloat before renaming the file and trying to upload it as a new project.
P.S. There is another server, code.appinventor.mit.edu with a larger limit, but it is one version behind ai2.appinventor.mit.edu, so uploading it there might not work.
Also, it is better to work on your appetite first.