It's what you're missing and it's ruining your life! Vitamin deficiencies will fuck you up, literally. Anxiety, depression, fatigue, immune health, testosterone, eye function, organ function in general, skin health... the list goes on and on.  Running your body without vitamins is like running your vehicle's without oil, brakes, and a failing electrical system.  

At a minimum, if you have anxiety and depression you should be taking vitamin A, B Complex, B3, B12, C, D, E and a few other. If you notice an immediate difference / relief, you'll know you're severely deficient and you can easily cure yourself in a matter of weeks or months.