I've been dosing 5000 IU's a day for six weeks. I have to say my bodybuilding and strength endeavors have vastly improved. I'm stronger, leaner, bigger, and am sleeping at night better. However, I have had a heavy increase in anxiety and my libido and morning wood are quite diminished. I recently read that higher doses of magnesium and vitamin K are mandatory when mega dosing d3. I just started taking 1500 mg magnesium a day and am dosing the K per label directions. Anybody experience anything similar?