Recurrent post natal anxiety and depression

Hi, am clutching at straws at the moment and thought it might help to hear from anyone who has had recurrent PNDA with each instance being different?
I had deep depression with my first and was mostly consumed with the usual I'm not good enough, everyone would be better off without me stuff but managed to get well again with help. Then the panic attacks and anxiety hit me when I was pregnant with #2 and I worked through that and now #2 is almost eight months old and here I am again but I'm just consumed with rage and get these angry fits when I'm stressed where I can't think straight and am constantly stopping myself from hurting one of my girls until finally my partner comes home and I can walk away. Then it's crying and feeling numb until it happens all over again. I'm meeting my with GP in a couple of days to start trialling medication but I feel like I've got Mount Everest to climb and I don't know how to open up about any of this to my partner he'd be horrified. None of my mum friends have had any mental health issues and they're very frank and honest but I just feel like a whinger and don't want to bring everyone down all the time.
Sorry for the waffling on.