I've lost all my documents on keynote, pages and numbers, which were supposed to be 'saved' to iTunes! How do I get them back??

I had a lot of presentations, spreadsheets and pages on keynote, numbers and pages on my iPad which was all 'saved' to iTunes. I temporarily uninstalled the apps as I needed the memory. When I reinstalled the apps about a month later, all my documents that were supposed to be on iTunes have disappeared! I can't find them on iTunes on my laptop or on iCloud either. Is there a way of retrieving them or have I completely lost it all? So dissapointed. Thank you for any help in advance!