iCloud junk mail filtering

Hello, all. I'm new to this site so please bear with me. I'm using OS x Yosemite with all of the latest updates. Recently I've had an issue in which the vast quantity of my iCloud mail is put into the junk folder and there is no option to "mark as not junk' the only option available is is "mark as junk' I have rebuilt the inbox, rebuilt the junk folder all to no avail. I belong to an email list and even my own messages are filtered into the junk box. I would greatly appreciate any help anyone can provide here.