Splendide, if you take nothing else away from this thread then please believe people when they tell you it WILL get better.
I had PND with my first two and was pretty much like you are right now. It was fucking horrible, I wanted to die, I wanted to give my dc to whoever would take them and run away and keep running. It took me 3 months with dc1 to finally see I needed help. I would urge you not to wait that long. The help is there. The tablets DO work. I am living proof!
You are doing an amazing job just having got to 8 weeks, those are the hardest, without a doubt.
My advice is to take each day am hour at a time. Don't even think about the hour after the one you're in. Have a goal for that one hour. Small things like do a wee, brush your teeth, turn the washing machine on. Keep it all small and only things you know you can achieve. Watch a half an hour programme. Very slowly and very surely you'll start to see you can achieve things. Feel proud of yourself for doing those things. Later in the day think of all those things and you'll be amazed what you did. It sounds weird being proud of yourself for these every day things but its these things that can overwhelm you and feel insurmountable right now.
With the feeding I abandoned breastfeeding and it was the best thing I ever did. All of a sudden a routine started to emerge and i felt a bit more in control.
It takes time, alot of time. But honestly in afew months time you'll look back and be so proud of how you coped.
Please go and talk to your gp asap. Get an emergency appt, I called mine up and they refused to see me and I literally just had to utter the words I think I've got PND and they saw me immediately. They are very very up on these things these days, they will help you.
Your dh will feel useless for a while but keep the communication open. Get him to read about PND himself so he can maybe understand its something you are not in control of (mine was good but couldn't grasp why id be depressed as we have a lovely house, good jobs, - if only that was the answer!!)
Good luck for the day ahead.