My vit D was down in the single digits and I was having all kinds of problems including substantial weight gain. Doc prescribed 50,000 IU / week. Did that for a couple of months and now I am taking 6,000 / day plus getting more sun.
I feel a whole lot better and was able to take off a good deal of weight.
About 4 years ago mine made me do the same thing, 50,000 for a couple of months , then 2,000 daily. She recently upped it to 5,000. I was skeptical but the first thing I noticed was I wasn't dragging myself from the parking lot to the building at work.