I have been diagnosed with PPD and anxiety and have been taking Zoloft for 2 weeks. The anxiety was so bad that I couldn't sllep even when my baby was asleep. I am currently taking 50 mg of Zoloft and my sleep pattern had been regulating, but now it seems to be back to where I started. How long should it take for Zoloft to be effective and is it possible that I need a higher dose? How can you tell? thanks . This has been the worst experience I have ever had. I'm so glad your story ran tonight ..it helped me so much.