Always take Calcium with Magnesium (taking just Calcium without Magnesium can make more harm than good for your bones; up to 50% of your Magnesium is stored in bones, only 1% in the blood). Also, take Magnesium with Vitamin D to help in Calcium absorption by 5 times! Magnesium should also be taken with vitamin B6 to help with the absorption of Magnesium.
The max RDA for Magnesium is 310mg (for females). The best sources are green veggies (spinach), black beans,nuts, seeds, whole grains, fish Halibut.
The most distinctive signs of low Mg are unexplained ulcers in the mouth area. Also, irritability, hypertension, feeling of tightness in chest, allergies, numbness and tingling sensation, osteoporosis, breast tenderness etc.
The max RDA for Potassium is 3500mg. The best sources are: bananas (1 banana=420mg), oranges, strawberries, spinach, tomatoes, potatoes. Signs of potassium defficiency are: thirst and frequent urination, tingling sensation or numbness in exteremities, low blood pressure, anxiety etc.
My multivitamin/mineral supplement has only 50mg of Mg and 7.5mg of Potassium. Therefore, I am taking one extra tablet/day of each, Potassium and Magnesium only, I guess I could take more if needed. Listen to your body and adjust accordingly. The best source should be the food, and when adding extra supplementation, start gradually, because too much it at once can cause the similar side effects as a lack of it.
You can test your blood for Hypothyroism, just in case, but most likely your symptoms are caused by lack of the essential minerals (Mg and Potassium as mentioned above.