B., talk to your careprovider, your therapist, and/or a lactation consultant about other options. You have received that advice from others already. If your doctor is not well-informed with regards to anti-depressants and breastfeeding, then make sure you or he consult with someone who is. It's not fair to you or your baby to be placed on medications that don't work and have side-effects.
I would also like to recommend a book to you. It won't help you with your immediate medication question, but may provide you with insight as to what is going on inside your body and you may come across possible therapy suggestions that have not been recommended to you.
Women's Moods: What Every Woman Must Know About Hormones, the Brain, and Emotional Health by by Deborah Sichel and Jeanne Watson Driscoll
These two ladies were the first to ever consider the influence of women's hormonal cycles on the effectiveness of medications, especially also during the period of pregnancy and postpartum....