Frightened child symptoms and conditions

I've been on Wellbutrin for about five days and have experienced a flu-like haze, headaches, upset stomach, and at the time of this writing (it's 3am), severe insomnia. Worst of all are the dreams and waking feelings of fear I am currently experiencing. I feel like a frightened child in the dark, almost like a panic attack at times. These thoughts and fears are completely unjustified and irrational. I am not using any other drugs in my life now, including alcohol. Worst feelings of fear I've ever felt; like having a nightmare but you're awake.