Loss of energy, fatigue, dizziness, headache ... are classic symptoms of LOW POTASSIUM LEVELS.

Most multivitamin-mineral supplements contain 10 or sometimes 30 mg potassium in their formulations. That's not NEARLY enough. You can take extra potassium as a separate supplement, but the least expensive and convenient way is to use a salt substitute, such as NoSalt or there's a product in the US called Morton's Lite Salt. I see you're in Singapore ... you may be able to purchase such a product from a grocery or possibly a pharmacy/chemist ... where salt substitutes are sold (for people who are on salt-restricted diets)

Read the label, and make sure it contains just potassium chloride ... Dissolve 1/8 tsp (0.5 ml) in a glass of water, and drink up. That amount of product would provide approx. 320 mg of potassium, which is equivalent to the amount in a large banana. You may choose to do this twice a day, morning and afternoon, just for a few days, until you're feeling better, then once a day should be fine.

If you are only able to find a product that is a blend of regular sodium chloride salt as well as the potassium salt, then just use it as you would to sprinkle on foods ... also is fine to use in recipes and cooking just like regular salt.

The other folks' suggestions are good too, and make sure you are drinking lots of carb-free fluids ... dehydration can make you weak and dizzy as well.

Keep us posted how you're doing..

Doreen