Did you delete the tree, or has the sync link just been broken? Are you using FTM 2012?
If you did not go through the delete process, which asks for your password an extra time and asks are you really sure, the data is probably still there, just perhaps hiding.
Can you access the tree online, from ancestry.com?
In the right hand panel of FTM, is the name of the tree listed? (see attached screenshot)
If it is not listed there, try opening from File>Open and then navigating to the folder where your FTM file is stored.