AdCal for Vitamin D Deficiency

Hi i have been suffering muscle pain, bone pain, weakness in muscles no strength, serious weight loss, no energy for 2 years now without anything being found until recently. my vitiam d level has came back very low, i have now been given Adcal-d dissolve to take twice a day which consits of 1500mg/400 I.U. effervescent tablets. 400unit/ calcium carbonate 1.5g , am i getting the rightamount of treatment ? I would like to know as the doctors have been useless in my case and i have suffered for a long time and would really like to see if this can help my case.