Breastfeeding & Zoloft

Today went to my counseling session, and right away he sent me to my doctor. He said I had moderate to severe postpartum, well the doctor feels strongly that I should take the medication. Asked if I could stop breast feeding for a while and take it or I can take it but she don't know how much of the medication is going to be passed through the breast milk.... I have no support from nobody I'm alone and don't know what to do I really want to continue with my breastfeeding ...