Open Question: What are some alternative medications to Sertraline? Anti-depressants?

My psychiatrist has decided to increase my Zoloft dose of 50 mg, because it didn't seem to work, I feel even worse … but I really do not want this drug – because it is making things worse , but also because I'm pregnant, I know that this drug will harm my child. But I must resist depression and now, I would like to know whether there are more appropriate drugs at the same time, I was lithium (900mg), in order to make it more difficult for tricyclic antidepressant …. I can not, because they make me crazy. Please help ….