Dear sir If you R taking bupropion for your anxiety and palpitations it's of no much help. There are other drugs like escitalopram which have better effect with out any side effects. U can change over to escitalopram or fluoxetine. Both of them are also safe on long term use and have better Effect in controlling anxiety and palpitations.

Please report the disorder for which you are taking bupropion. If its depression or anxiety disorder then it might be explainable by the disorder. Also bupropion can precipitate

It happens with the beginning of treatment, it will go away with time

It won't be there,  intially it will take some time to adjust, it will settle down.