I can really relate to the intense disappointment of a birth experience turning into something completely different than you dreamed of and being long and awful. In all honesty, I am still mourning for the experience I wanted and still sometimes feel angry at myself and others for feeling pushed into an inappropriately timed induction. I take solace, though, in seeing my wonderfully healthy full term boys who are getting more amazing every day.
About a week after they were born our nursing relationship was terrible. They had some really bad latch problems from TMJ due to their vacuum extraction. Every time they wanted to nurse, I wanted to run screaming from the room. I hadn't figured out my breast pump yet so I broke down and gave them formula for a couple of feedings. Now, I suffered from depression for years and there was only one other time in my life where I experienced a sense of despondency as deep as I did that day. It was terrible. I felt like a total failure and wondered how I could make it and why I had to deal with having twins... I wanted a hole to open up in the earth and swallow me.
But now here we are, nine months later. That day is the only time they have ever had anything but breastmilk. We've figured out ways to get out of the house. I find time to cook meals. We have fun playing together. I can't relate to how hard it must be for you having other children who also need your love and attention but just from reading from other MoMs I see that it can be done (you all deserve medals, btw).
I hope that you can find friends and family to help you and cook for you and let you take a shower or a walk by yourself. I hope that you and your partner are able to communicate really well with each other through this difficult time. I hope that the love you and all your children share will carry you through your doubts. Hopefully you'll be able to look back on this day and pat yourself on the back for how far you've come and how much you've grown. Just having these disscussion boards to turn to has helped me a lot... the mamas here are so supportive.
Good luck... I really do think it will get better.