Hi OP, I can really relate to you, and offer hope.
I had terrible PND and OCD after my son was born, I couldn't bond with him at all, felt numb and like I was in a different world, and then started having absolutely awful terrible intrusive thoughts.i honestly thought I'd gone mad, particularly when mixed with sleep deprivation.
It all came to a head and I went to a and E in absolute crisis when I was about 11 weeks pp, convinced I would harm my baby and that I would never bond with him. It was the bleakest time, so I really really feel for you.
However, he's now two and a half and I absolutely ADORE him. Recovery was slow going- could you ask for a referral to your local perinatal mental health team? Most areas have them and they were amazing for me. I had therapy, bonding help as well as taking sertraline.
Things didn't get better overnight. The obsessional part of the OCD especially was difficult to overcome, and I still find myself slipping into obsessive thoughts and behaviours when I'm run down or tired.
But I wanted to offer hope. I'd literally written myself off for every being able to look after or love my baby, honestly, I thought he was someone else's, and I was a terrible human. I won't say I was suicidal, but I did think I wouldn't be able to survive it.
The bond we have now is glorious. I'm by far his favourite human, and vice versa. He's great company now he's talking, and I don't feel at all anxious when it's just the two of us (I used to have panic attacks in the same room as him)
Sending love. It's a shit start to motherhood, I know, and it crap that it's happening to you. But shit starts can be overcome. The first months seem so important, but now I'm through that time, I can see that my baby actually had no clue what was happening, and that now I have all the time in the world to bond with him.
Take care, and I really hope you get some good help. It will get better x