Talk to a doctor. They will not take your baby away. I was suffering from extreme depression during the end of my second pregnancy. (I have a six year old and a two year old.) I wrote my husband a note saying that I was leaving. I just wanted to die and I felt so guilty and ashamed because I had a special little girl and a sweet baby boy on the way. The next doctor's visit my husband brought the note and showed it to the doctor. She said there is no way that I should go on feeling like that and put me on a medication. It was risky considering I was pregnant but it was something I HAD to do. After I had my son, I switched to a different medication with a lower dosage and it helped me greatly.
Don't feel alone....just because no one talks about it doesn't mean they aren't going through the same thing.