switching from zoloft to wellbutrin

I took zoloft 50mg for about a month along with xanax 25mg for anxiety with no change in depression.  my doctor increased the zoloft to 100mg once a day and xanax 50mg 4x a day and still no change after another month.  now she has me on wellbutrin 150mg 2x a day and been on it for a week with very noticeable side effects.  I shake constantly, my head feels weird, i am very dizzy, neusea occasionally, no appetite, have no concentration, and sleeping is very difficult.  I feel more depressed and not sure if its the switch or the medication.  not sure what to do i need some advice.  I have been in contact with my doctor every month and she is just trying things to see if they work she isn't sure whats wrong with me.