Hi, I totally empathise with you and the first poster in this thread.
You're sounding really stressed which is totally understandable, with the 'physial and mental exhaustion' and 'craving sugar', it sounds like your adrenals are quite stressed....I'm sure you don't need me to point that out to you!!!
Anyway, dare I suggest another supplement.... try some ashwagandha for one month, it balances out the adrenals, will make you feel calmer and have more energy. Perhaps it will help you focus more on what you're trying to do.
In the meantime, I presume you have omega 3s in your diet? I find these helpful and satisfy my brain esp eaten with some protein (and I have really out of control Sugar cravings too).
Also maybe try some flower remedies (N.B. they have very very tiny amounts of alcohol in them which you may not be able to tolerate). If you think you'd be ok with the alcohol, I highly recommend Rescue Remedy or any other emergency essence. Do a google on 'flower essences'.