What about sleep, caffeine intake and stress level? How are each of those things as well as how are they in relation to how they were five years ago?
I do think it may be overtraining, to which your body has slowly developed an intolerance. I'd also drop the nuts in favor of something less inflammatory, and add a potato or yam to dinner - there might be a tiny bit of water weight for the first couple of days, but it won't last.
Do you get lots of salt with all of that water intake? Adrenals need salt! You should also be supplementing magnesium if you aren't already. Natural Calm at night is great.
Life is not a matter of having good cards, but of playing a poor hand well.
- Robert Louis Stevenson