Postnatal depression??

I do have history with depression and I was on medication but I stopped when I got pregnant but now I think iv got pd I just can't seem too bond with my 7 month old premature baby like I have with my 3 year old there both got different daddies but I feel like the worst mum ever because I can't seem too bond or love her as much as I do my first child? Maybe it was cause I was made too keep a child when I knew I couldn't cope I don't no but has anyone been through this there's more too the story but don't really wanna go into detail but if I went too doctors for help with social services get involved? Please kind replys I'm heartbroken as it is! And will I be able too get a bond and love her? Like a mummy should do 😭😭