Vitamin D deficiency

Hi all. I’ve recently been diagnosed with vitamin D deficiency, along with my many other illnesses. My dr has started me on a supplement, but it’s quite a large dose and I just wondered wether anyone had any experience themselves? I’m a registered nurse and to me it seems a very high dose quite regularly! Anyway, any advice and experience would be great!!! On the pack it has vitamin D 20,000 and on the box says one tablet every two weeks, but my dr has over ruled that and says start with 3 tabs a week for 5 weeks then one a month for maintenance. Thanks again ♥️♥️