Ah tell you whut...
I had a little too much coffee back in early Feb, didn't enjoy it one bit so I reduced my sugar intake drastically and stopped drinking caffeine for around 7 weeks. The only sugar I got was from meals, no sweets or chocolates.
It does a world of good to the old mental box. Found that my sleeping hours were stabilised and I always got a full 8 hours sleep, didn't feel tired during the day. Was great actually!
Back to normal now though. It's fun abstaining from things like that just to see what it does to you, but it's no something I'd be happy doing all my life.