Just wanted to add to the many offering support. You are doing just fine, recognising the problem and doing something about it is the hardest step.
I suffered PND from when my younger son was about 7months old. Trouble was, I had no idea. Thought it was just what it was like having 2 kids. I was horrible, just horrible. And I don't remember most of my son's first 4 years, which is a bit heartbreaking. Thankfully, I realised when he was 4 1/2 that something was wrong, DH and I separated for a few months and the doc said PND could still affect you YEARS after a birth.
I took citalopram for 18 months, but it did take a couple of weeks to really kick in. I also took temazapan 2/3 nights a week to help me sleep. Letting go is very hard to do and, like you, I had a very supportive DH who totally helped me work through it all. Even now, 4 years on, he knows when I need support or when I need to be kept away from potentially stressful situations. Also, if I need to sleep, he knows that I really NEED to sleep and there just is no point in fighting it.
I had almost no support from my family, and my inlaws weren't overly interested so I really really relied on online friends in the beginning. But one day I opened up to a load of school mums when we were at a soft play party and they were Sooooo ku d and helpful and just nice. I think I had always seemed a little stand-offish so they were glad to find I was human! And I get on brilliantly with them all now and people even ask me for advice when they experience depression issues themselves 
You WILL get through this, your kids will not hate you, and your DH will be thrilled to have happy-you back in the very near future. You need to take care of yourself now, give in to your feelings and needs, abdicate responsibility for yourself in a way, let your DH take control. And please try to talk to other RL people about it. If you're anywhere around Cambs/Herts, I would love to meet you for coffee if you felt like offloading to a stranger 
Hugs and good luck to you all