Projects disappeared from menu

hi,
For some reason this morning when I logged into wp, the ‘projects’ tab was missing from my menu in the editor. Thankfully, my existing projects are still online and there are no problems with them, but I am now unable to add new projects or access them from the dashboard. I tried a link I had to a draft project I had made yesterday, and it returned an error for page not found. How can I get the projects tab back in the menu? I did not set up the website but have since taken it over, and do not know if it was a plugin (or which plugin) that was being used to create and edit these projects, and can’t think of any reason why it would have been deleted. The link is to a project that is still online and unaffected.
Thank you!!

The page I need help with: [log in to see the link]