Hi,   I'm a 31 year old woman.  This summer because of my age and wanting to avoid wrinkles I used put 30spf on my face and 15 spf on my body every morning before I went outside.  I had started feeling tired out for a while and needed naps every day.  Then at the begining of august I was just overcome with fatigue and could barely get out of bed.  The mental fatigue is the worst it feels like I'm sleep walking through my days.  All my tests we're normal except I had a vit d level of 15.  The doctor put me on 50,000 iu a week.  I've been on that for 10 days and only taken two pills.  I have noticed an improvement in my energy levels but I'm still tired all the time.  Can anyone tell me how long it will take for me to feel better again and have mental clarity?