Okay - I really have to tell this...
I didn't eat any breakfast today - just green tea.
I was feeling turbo-uber-sick right after that.
Then at the sports center, I drank about 2 litres of water.
My stomach started hurting like HELL!
>__
My thought is that you should put a lil OOMPH in your breakfast. Try eggs. Not a popular choice with some, but if you can eat them you'll feel much better throughout your day.