I just recently went from Lexapro (20 mg) to 25
mg of Sertraline. I saw a psychiatrist last week, though, and she said that
20 mg of Lexapro is equivalent to 100-150 mg of Sertraline, so I was dosed too low. I would see about gradually upping your dosage. I took 25 mg for two weeks, 50 mg for three weeks, and last week went up to 75 mg. Next week I start on 100 mg. I had terrible headaches, dizziness, and nausea for about three and half weeks, but they've now subsided.