Not sure if this is side effect. Had Thyroid Cancer, Had radiatio...

Not sure if this is side effect. Had Thyroid Cancer, Had radiation. became hypoparathroid. Taking large doses of calcium 7200 mg. daily. Taking 200 mcq Synthroid daily. Still hypocalcemic, just increased calcium to 9000 mg. daily. Having heart palpatations so severely, my head feels full. It lasts approximately 1 minute with each episode, skin is really dry, even peeling, leg and feet cramping, finger, hand and arms have episodes of tingling, and hair texture has changed.Doctor has tried to regulate calcium and synthroid for almost 2 years now. Is this normal??