Way to much trouble with taking bases.

I have noticed, especially in my PvZ (I am a protoss player) that i have a major issue taking and maintaining other bases. I was pretty comfortable with being on 2 bases, and after reaching and getting stuck at rank 1 gold for a long time i realized that a lot of my problems come from when i have to take that dreaded 3rd base. When I have to take a 3rd base my aggression, map control and macro slips very hard, or when i hear that mineral patches are depleting, i just all in. Are there any tips or tricks I can use to help with the later mid game, base control, aggression reminders and such. I know this is a very broad question but any help would be awesome. Thanks in advance.