 [ Symptoms ] vitamin d level was 15 my doctor prescribed 50 000 iu every other day details are below so my vitamin d level was 15 last year i did nothing about it unfortunately but i was  always sleepy   i would take long naps during the day  i can not concentrate   anxious  knee pain once in a while it starts hurting and feeling really stiff goes away with rest i feel bad because i am in college and i do not have time for this i have lots of work to do do you guys think this is because of my vitamin d levels also what other tests should i do to determine the cause thanks a lot [ Disease ] i got checked by my doctor who informed me of this situation he suggested i get surgery i was hoping for an alternative