First off, HUGE hugs, hugs every day. Hugs to you, your husband and your baby.
It WILL get better.
Depression and anxiety are terrible beasts ,you are meant to be a parent and have that baby. They are so scary, and looking into that pit and not seeing any light is terrifying. But there is light, and you will come out the other side and be so much better for it.
I'm so proud of you for reaching out for help, it is so hard to do. Is there a support group in your area you could look into? google "post partum support *city you live in*"
Zoloft does take a couple weeks to work, and you maybe need the dose increased a bit. Did you tell your OB about the anxiety attacks as well? you might need some ativan to help with that.
I would also suggest finding a therapist near you to get some coping mechanisms.
Is there a family member near that could come and help until you get yourself back a little bit? Or you could post on craigslist for a mother helper, or even post in the "tribe" section here.
Take a deep breath, every day is a victory. IT WILL GET BETTER. I will hold you and yours in my heart every day.