Something is consuming all of my iCloud space

For nearly a year my iCloud account has had about 80 GB of data in it, but today all 200 GB were used up inexplicably. Under "Manage iCloud" my usage is the same as it has always been, and adds up to about 80GB, but for some reason it says that I have 135 GB worth of "documents" though there is nothing showing that kind of usage in the breakdown! Something is clearly wrong. Also while I was trying to figure it out, the total size of my contents was under 1 GB, but 15 minutes late it went back to what it was. I deleted 16 GB worth of data but it didnt change my usage whatsoever. Clearly something is quite wrong with iCloud.