storage full, but my stuff is empty

Check all these locations for any files that count towards your storage limit:

https://assets.adobe.com
- check also the deleted files section - files are permanently deleted after 30 days; delete files manually if your storage is full. 
https://lightroom.adobe.com
https://documentcloud.adobe.com
https://express.adobe.com/sp/
https://new.express.adobe.com/
https://assets.adobe.com/mobilecreations
- in the Mobile Creations area also check Deleted items.

Here's the help article about cloud storage and what is included as you may use other parts of it e.g. Libraries or Lightroom, that you haven't mentioned here:
https://helpx.adobe.com/creative-cloud/kb/file-storage-quota.html