I did a bit of research last year when the doc told me my vitamin D levels were low. I started taking an OTC vitamin D supplement, but apparently six months later they are even lower than before. I'm outside a lot (I know the sun has a lot to do with vitamin D synthesis), but I am also a type one diabetic. Not sure if that has any effect though! Anyone else suffer from low vitamin D levels? Does it make you feel different? The doctor wants to put me on a prescription supplement which I will start this upcoming week. I do find I get into bad moods quite easily lately, but I just figured it was from the frustration of dealing with my diabetes.