Wellbutrin and stomach pains

i have been taking wellbutrin to help me deal with anxiety for a little more than a week. i thought it would take more time to have an effect, but i feel very calm. i even stopped smoking right off, which i didn't intend to do. The side effects are worse that i thought they would be. i have lost the ability to spell, my short-term memory is noticeably impaired, and i have trouble paying attention in class/at work. i feel very foggy and disconnected. i've also been having headaches, night sweats, and stomach pains, but they are mild.