I would highly recommend eating potassium loaded foods as well as things with B12.

Potassium= Apricots, Baked Potatoes, Squash & leafy greens. Saltine crackers actually also have a high amount of potassium.

B12= Shellfish, Red meat & Dairy or B12 liquid drops.

I feel burning all day everyday and worse at night, the all over body tingling I don't get but I know it can be a sign of a severe nutritional deficiency (dangerous) usually electrolytes are out of whack. Add the racing heart and I would not mess around and call your OB or go straight to the ER. It may have nothing to do with RSD so better get checked since you are caring a precious one At least that is what I would do in your shoes.

Be well,
Tessa