Yeah, 10-14 days is fine and usually mild. It's anything beyond 21 that these things become an issue.
If one is deficient, transitioning into the fast is hard. The first 3-5 days are rough, detoxy...
Very mild low electrolyte symptoms and vitamins and mineral deficiency are things like head ache tingles and twitchiness. Mood-wise one would be feeling on the down side.

In my very ignorant and humble opinion, one can during a Water Fast soak in epsome salts, potash, and magnesium chloride... I'm have even drunk pinches of these in my water as one would with Himalayan or Celtic salt. Bicarb, calcium powder and food grade diatomaceous earth... All those have helped me continue a fasts while I was extremely deficient. I, like you, eat a very clean and nutritious diet and was still deficient...


Minor things can be tolerated..(twitchy,moody,tingly) but as soon as anxiety/panic attacks and heart arrhythmia set in, I would abandon the fast and terminate it. Remembering that it will take a faster possibly weeks to refeed... It takes me a week to just get into solids, esp being deficient, the digestion is so much more depleted and needs extra time and care taken.

I have seen deficiency go wrong... Not only from my self: where no matter how much I pre-bulk prior to a fast, after 21 days I suddenly turn freakishly thin...
But I have seen another loved one who was extremely b1 deficient...
We were talking as usually, the suddenly lost control of their limbs, and the lost cognition of language altogether or how to communicate!!! Very very suddenly...
https://en.m.wikipedia.org/wiki/Beriberi
https://en.wikipedia.org/wiki/Wernicke%27s_encephalopathy
https://en.wikipedia.org/wiki/Ataxia

That was one of the most unimaginable experiences. They were in and out of consciousness... I quickly realised it was a vitamins b deficiency and as they were in and our of consciousness I gave them molasses and bone broth and they recovered over a few days.

Be aware! Death is closer than one may think!!

Deficiency can be tricky... Sometimes you ruby absorb some nutrients without the other.... And if your deficient in so much then it's tricky again.

Best wishes hope you find a solution