My psychiatrist just recently had me try Prozac for the first time. It was supposed to help with my depression and anxiety, including my panic attacks. To sum it up - horrible, hellish experience. Will never use again.
Basically got the paradoxical effect of it. I've always been a really quick metabolizer of drugs, so I felt the effects almost immediately. I took one 10 mg tablet, 5 mg the next day, and another 5 mg the third. It just kept getting worse. At first, I felt manic and energized and happy, but then moments later I'd start to have a panic attack for no reason at all. I was very nervous, easily agitated, and panicky while somehow being manically happy at the same time.
The next couple days were worse. I started feeling really aggressive (very unusual for me; I'm very non-violent.) I had weird urges to hit people. I wanted nothing more than to be completely alone. Everyone was bothering me. I was zoning out all the time at work. I could barely taste food when I ate. I felt either completely apathetic or on the edge of a panic attack constantly.
So the third day, the depersonalization got really bad while I was trying to sleep. I felt like someone else was wearing my skin. I didn't panic like before, but I got extremely agitated and depressed. I cut myself worse than I ever had before to calm myself down, and I couldn't stop thinking of suicide. I had never seriously contemplated suicide for even a moment before Prozac. And so that was it - decided to quit taking it immediately. I felt relief after only a day of being off of it.
I guess it works really well for some people, but I will never take it again. Nevereverever.
tl; dr: side effects were increased anxiety, mania, depression, suicidal thoughts, dramatic loss of appetite, irritation/anger/moodiness, strong emotional blunting or "numbness", insomnia, and depersonalization.