My vitamin D level was 10 too! I took 50k once a week for 2 months, I was first retested after four weeks and it was only 18, so I continued for another month and my new vitamin D level was 50. My doc said you want your vit D to be at least 30, but I have rheumatoid arthritis as well, and the doc wanted it even higher.
My low D levels came from Celiac disease, an autoimmune intestinal disorder. Despite getting lots of sun here in Florida
, my body just was't able to use it.