I actually think it might help you. Provigil has been shown to increase dopamine and noradrenaline (norepinephrine) in the striatum and nucleus accumbens, the latter of which is an integral part of the brain's dopaminergic reward pathway. Since "withdrawals" from amphetamines are most likely the result of depleted levels of dopamine (and, possibly, norepinephrine) in the prefrontal cortex, taking provigil during amphetamine cessation would most likely at least partially replenish your suffering levels of dopamine/NE.
It certainly is not dangerous to take provigil during amphetamine withdrawal, so you might try it out and give us a report back. But from a pharmacological viewpoint it would make sense that provigil would ease the symptoms, although perhaps not as much as amphetamine itself or a related derivative.
Additionally, I wanted to throw it out there that snorting Vyvanse is a complete waste since it is a precursory drug to dextroamphetamine, which it can only be converted to during digestion in the GI tract.
Lastly, I would urge you to reevaluate your use of amphetamines. I don't want to sound like I am preaching, because I have abused amphetamines enough in my life to experience amphetamine psychosis. On top of all that, chronic high-dose use of amphetamines has been definitively linked to irreversible degradation of dopamine receptors, meaning that you may be feeling lethargic and shitty for a LOT longer than the typical withdrawal lasts. We're talking years, if not a lifetime of impaired neural functioning.
It's just something you ought to be aware of, but it's most certainly your life - I want to stress that. No judgment from my side of the screen, here, as I have been there before, doing what you've been doing - and much worse/for much longer - a few years ago. I am now settled into a daily regimen of dextroamphetamine for adult ADD, but I do not abuse my meds any longer............ and I am now able to function normally.
Peace and all that stuff
~ vaya