Afraid to stop Prozac

My dr has has me on prozac since march 2 2010,differnt doses but i got up to 50 mg for 4 days and when i went to see him he told me to srop the prozac..(i have been on wellbutrin sice june 10 2010) i told him i wanted a taper so he said drop to 30 mg for 3 days and then 10 mg for 3 days and stop  it,,,i have a trip planned to alaska on uly 9th and im so afraid i will get bad going off the prozac it was helping me somebut som many sidde effects...im doing a bit slower taper,im also on xanax and adderaal 5 mg........i just dont want to flip out i was till depressed on the prozac and the wellbutrin but something was helping some i hope its the wellbutrin..........will it cover the same things prozac did with out the side efeects,i dont know if my anxiety but in these 3 days i cut from 50 mg to 40 prozac i feel anxious and headache i was only on the 50 mg 4 days before that i was on 40 mg for a week and most of the rest of the time i waas on thirty mg..i just want to enjpoy my alaska trip