Just because you take a multivitamin doesn't mean you aren't deficient. Unless you're horking down 6+ of them a day, they almost certainly don't give you enough magnesium, a mineral in which the majority of people in westernized countries are deficient. Your multi probably doesn't give you 5,000 IU / day of Vitamin D, the other nutrient in which most people are deficient.

Take 2x of these Vit D3 + K2 per day, in the morning, for 2 weeks, then reduce to 1x / day. Also take 2x of these magnesium glycinate every day at night, plus another 1x anytime you have an extra strong urge to take a daytime nap. Also check that your multivitamin is a good source of iron. If not, and if you also don't eat much red meat, throw in 1x iron bisglycinate per day in the morning.