Lost my categories/category menu

Wow!

All my internal pages of my site are suddently giving me 404 errors. Then I notice that I no longer have my category menu nor categories to choose from. this is how I figure it out while I was writing a new post the category wasn’t showing up in the permalink (year/category/postname is my structure)

I wont panic yet knowing usualy it is simple but a bit freaky 🙂
Thanks