iCloud Drive won't download Pages and Word Files

I have been using iCloud for a while now, and up until a few weeks ago it worked perfectly. Out of the blue it won't work anymore. I use an MacBook Air for college and at home I use my iMac, and the constant uploading of my Pages and Word files is amazing.. that is, when it works. I can't think of any reason why Drive won;t upload my files anymore. When I open Finder, I can see all my files and some of them I'm able to open, but most of them have a cloud with a down arrow in it and it says it hasn't been downloaded. This is the case on both my MacBook and my iMac. By using a browser opening Drive I can download the file to my computer and afterwards in Drive, but even then it won't download automatically. What can I do to solve this annoying problem? Thanks in advance!