I have had a B-1 deficiency and my hands/feet were falling asleep way too often. I also had a really hard time concentrating. B-1 helps to convert blood sugar into energy (which can explain why you'd feel tired). It also is important to keep your nerve endings in good shape, so being low in B-1 would explain tingling in the extremities and diminished brain power.
Definitely let your dr. know about your symptoms. Blood work should cooberate it. Personally, I've done two rounds of self-administered shots and am finally 'over' the deficiency but will have to take the supplemental B-1 pill everyday. I've been doing really bad about remembering my daily vitamins, though.

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