I keep getting a Icloud pop that needs my password and it won't go away. How can I fix this?

I keep getting the pop up message: "Photo Stream- Photos for the iCloud account .....cannot be accessed. Review your account information in System Preferences". It just keeps popping up over and over and over again and every time I try enter my password or try to reset my password it says it is incorrect. I've reset my password so many times now and it never takes. If I sign out of iCloud will any of my photos be deleted on my Macbook? When I try to sign out, it threatens me that it will delete any photos that have not been uploaded to the cloud. I think it has become self aware. Apple...is Skynet...anyway, what in the wide world of sports can I do to get this (!*$^# pop up to go away?!?!?! I'm starting to think my warm, happy family photos aren't worth this fiendish pop up.