PTSD and Depression

Yesterday I got diagnosed with PTSD and depression. Psychiatrist thought Zoloft would be safe. Since I am in my 3rd trimester doctor didn't think it's dangerous. He  said when I am depressed my body makes cortisol hormone and baby gets affected by this. He says taking Zoloft or having cortisol hormone in your body is in same danger level but at least Zoloft will help you sooner. Basically happy mommy happy baby. 
Anyone has used Zoloft before when you are pregnant? I am just not sure about it. But I need to get healthy.