Lost in the new Photos app.

I am so upset, right now. I spent two days editing pictures in the new PHOTOS app on my iMac. I guess I didn't completely understand what was happening, because I was treating it like iPhoto. My impression was that iPhoto was being phased out. In any case, I thought I had a nice, little album that I could share with Google Drive, but that wasn't happening (I could drag and drop files from iPhoto to Google Drive), so I share it to my iCloud account. 180 photos. What the other person received was 1200 + photos! I have no idea how this happened, but getting an album in iCloud was very confusing. Bottom line is, I want all my pictures out of iCloud and now I'm seeing something that leads me to believe that ALL of my pictures are in the cloud and shared? All? Like, 34,000 or so? Some are very personal images, some are copyrighted art. I did NOT authorize any such thing. I want everyone out of the cloud, now. How do I do that? Also, the most recent photos, are they in danger? The album only shows up in the cloud. please, help.