I recently had my routine check up done, and vitamin D levels, calcium and iron came out to be low. Doctor prescribed multivitamin tablets containing calcium, vitamin D3 and folic acid and Vitamin D3 oral shot once a week for 4 weeks. I just want to know that the multivitamins already contain vitamin D3 and that to be taken twice a day, will consumption of oral solution cause overdose? Kindly provide your insights since I am skeptical about it.