Vitamin D Deficiency and Prescription

At my recent annual checkup I asked my physician to test for Vitamin D. He performed a 25-HYDROXYVITAMIN D (TOTAL) test and my results were 24.3ng/mL. He has now prescribed Vitamin D (Ergocalciferol) 50,000 to be taken once a week for 12 weeks. After that he will test again. From what I read, Ergocalciferol is B2 and B3 is actually better. Should I be concerned? Thanks!