Playlist deleted in iTunes after connecting iPad2

Hello,

I am hoping someone can help me solve this problem. Storage for my iPhone 5 and iPad 2 (each 16 GB) was filling up so, to create space, I created a specific playlist to synch to each from my iTunes. I scanned through nearly 7,000 songs in my library and made a new playlist of about 1,300. This took several hours over the course of last night and this morning as I started from scratch. When finished, I synched my iPhone without problem.

However, when I connected my iPad to sync, all of a sudden the playlist in iTunes was gone. Vanished like it didn't exist. In addition, as I briefly checked through a few other playlists in my library I noticed that a few smal changes I made to them (while I was creating the 1,300 song playlist) were not reflected. It was as though all of the work and editing I did in iTunes since last night had never happened.

I'm not sure what to do. The music is on my phone, but my iPad is empty and the playlist no longer exists in iTunes. Any suggestions or advice without me having to spend countless hours trying to re-create another 1,300 song playlist - that might disappear again!?