Don't panic, Tiny - this bit is absolutely awful for a lot of people. I went completely mad and was googling fostering services and saying I couldn't go on and we'd made an appalling mistake, and I just wanted to go back to my old life. DS was a restless, agitated baby who screamed when put in his pushchair and hated the sling, and BF didn't work, and I had to be careful because I'd had a CS etc etc.
It wasn't PND, it was just that life with a small baby was (for me) absolutely appalling - I felt as though I'd died and gone to hell. A good friend said 'It gets better, and the old self you are mourning hasn't died, it's just gone into stasis for a while - it'll be back.' And it's true, in my experience. The thing that you can't see and that I can, is that this gruesome bit is actually pretty short, though I'l never forget how grim it was when it was happening. Your baby will start becoming a person, respond to you, and become a lot easier, and you will feel like yourself again. What's panic-inducing about it is that you think this is it, forever, my life is now just this. If you knew that in a fortnight, things would have changed completely, it would be easier.
I wish now that I hadn't let myself get so frightened and gone running around desperately trying to fill my days with activities which were supposedly good for the baby - time enough for that sort of thing later, and my son used to scream through baby massage/NCT coffee mornings, after I'd sweated blood getting him there on public transport on no sleep. If I had that time again, I would just give myself up to it, install myself on the sofa, feed endlessly, and watch box sets. I would postpone any type of activities or social life outside the house until everything was easier. Just hold to the thought that anything that feels unbearable is strictly temporary.
Best wishes. Honestly, this is the worst part.