discouraged

How do all you do this so strictly. I swear Im trying so hard to be disciplined. And I am succeeding mostly. Im finally off Sugar and coffee for almost a month now. That was hard enough, now Im off meat dairy and grains. Cheating on grains on occasion. But IM getting depressed off and on. Not clinically, but moody you know? Some days Im totally motivated, others I want to give up. Does this get any better? I miss my Starbucks and I dont feel much improvement since I quit Sugar if any.
Katie