Sounds like a pattern based behaviour type thing. Try to think if you've got any memories of things going badly in the morning. Or maybe you've been low in mornings and your subconscious is repeating this whether you're bad or not.
I dont find I cycle on days per-se, more on Months, so between March and June, my depression is worst especially in the mornings. I've started working on NLP to try and understand why this is but also (and most importantly) to break that pattern of behaviour.
What the practitioner I see has done is identify some 'triggers' for my low mood (and in some cases that can be as simple as 'the sun is out this morning'), we then work out 5 phases between that happening and me feeling bad.
He then swaps those feelings round so I get confused, now when I get the trigger, my reactions are altered, so the pattern is broken, and most of the time (I say this because it's not a magic fix and will take some practise from me too) I fall into the newly programmed behaviour.
As people say in this thread, it's a classic symptom, but this technique has helped me, might be good for others too?
