I was on Lexapro for 5 years for anxiety but it seemed to start to lose its effects. Started experiencing even more panic attacks and constant anxiety. Psychiatrist decide it was time for a switch so we crossed taper for two weeks going from 20mg of Lexapro to 10mg while starting 50mg of Zoloft at the same time. After those 2 weeks we stopped the Lexapro and went to 100mg of Zoloft. I have been at that 100mg for exactly 3 weeks. Didn't have a lot of side effects with the zoloft but lately I have been feeling more depressed and anxious. Never have experienced depression except for these last 3 months. I'm tired of feeling this way and I'm wondering what to do next? Is three weeks long enough to know if the zoloft is working or not?