Hi. My doctor recently changed my dosage of Prozac from 20mg to 40mg, and I was wondering, when will I start to notice a difference? I suffer with agoraphobia and panic disorder and am very anxious to get my life back. I've been on Prozac now for a little over a month, and I've noticed some change but nothing major yet. For the 40mg, I've been on for only 3 days. How much longer should I wait to expect results?