OS X 10.10.4 and iTunes 12.2 not updating correctly

My Mac said there was an update available for my OS. I opened the app store and selected "update all". The only updates were for OS X 10.10.4 and iTunes 12.2, and for iMovie. It's 12 hours later and they have not come close to finishing the download. My computer is working so slowly that is has taken me 30 minutes to get this posted.