just wondering how long it takes for fluoxetine ( prozac) to start working? im nearly on week 4. I have improved but not drastically. still crying a lot, being sick and feeling nauseous, not sleeping very well, headaches and panicky with the odd panic attack. I was previously on 20mg seroxat for 17 years but I think thats finally out of my system. just need the new meds to hurry up and work. any advice?