Sorry to hear you are running into this issue. Do you by any chance have a large asset (typically a video) still uploading or fail to load? This would be indicated by a yellow/red icon on the top left of the asset.
Here's another thing to check: without closing the current browser tab that has the project open, open another browser tab/window and load the project there; check if all your content/edits are saved and if you can download/share there.