While you are editing your campaign, do you see this style box above the block you're working in?
This will give you a Save or Cancel option while working within one of the blocks.
There is also a yellow global Save button on the right side of the page as well next to Preview.
Where you seeing these options at all when trying to save your work? If not, What browser are you currently using? Could you try saving some work in a different browser to see if you run into the same problem?