Interesting observation, if you buy into the addictive nature of sugar, this sounds like the talk of an addict. The very thing that makes you feel good has the effect of lowering your mood in the absence of the substance and it appears the only way to get that feeling back is more of the substance. One can even "know" that this is happening but feels helpless, even after many absolute resolutions to end the relationship with the substance that is causing harm. It's "baffling" as one branch of recovery states in it's dogma.

I really wish I could give you advice but can't. I can only say that for me, so far, has been abstinence from the harmful substances (includes for me substances other than carbohydrate). Then you have a chance to "feel" normal, which at times, is pertty boring

Boring, calm, peace and quite are what can be craved

I wish you well!