Please don't be afraid to ask for help. Your OB office can help you. Post partum depression is very common and treatable. As said above, you baby will not be taken away because you ask for help!
If your breastfeeding it may be the hormones from breastfeeding that are messing with you
They won't take your baby away for asking for help. They will evaluate you and see if maybe you could benefit from medication or help you come up with a plan for extra support at home with the baby. The reasons you are depression sound completely legitimate to me, not that that really matters, but just so you know. It's good that you are recognizing this about yourself but now you need to talk with your doctor and have a true assessment done. It will make you feel better to work on getting your mood better.