This does talk about ICS but the same could be true for GB. you need to find which app is stopping your phone going into deep sleep mode. Once done get rid of that app or update it;
https://www.allaboutgalaxynote.com/how-to-solve-battery-issues-after-ics-update-in-your-galaxy-note/
Are you running rooted firmware or sideloaded apps ? This could be caused by a malicious app. You could also try a clean factory install and install your apps one by one until you find which was causing the problem but using the linked process above is better.
