I'm scared....

I just recently had a baby and due to my mental history doctors, OBs, Nurses, ect have warned me throughout my whole pregnancy about postpartum depression even my mom warned me about it. Well now that I had the baby I've been feeling so depressed, I've ended up cutting myself again and the other night I told my fiance I wanted to sleep in separate rooms and I laid in bed with a ribbon tied around my neck hoping I'd pass out......I'm scared to talk to my doctor about this because I've been sent to mental hospitals three times in the past and I don't want to go back there I want to be here with my fiance and my baby but I also know if I keep this up and if I'M not okay I won't be able to properly take care of my baby I'm just scared to open up and ask for help because everytime I did it never ended well for me and I just want to be a good mom for my baby girl....I just wanna be good enough😔