Neenz This is the toughest bit, I promise. Your twins sound like mine. I couldn't get mine to feed/sleep at the same time and I spent night after night, feeding, changing, re-settling and just going from cot to cot. I would sleep in 20 minute bursts, hell.
My DP didn't help at all when I had my first child. Aside from the fact that I wanted to be up every minute my DD1 was, I didn't need him to. With the DTs, it was different......
He used to suffer from very severe migraine attacks. I thought if he didn't get proper sleep he would lay himself open to a bad one. But......I needed him, it was too much on my own. And my DD1 didn't sleep well either so I desperately needed the help. We both slept badly. We both took it out on each other. We both had those "fucking hell, I hate this, this is miserable and I want out" moments. And now we can laugh about it. Your DP/DH might get ill without proper sleep and so will you and therefore, everyone suffers. Much better to feel you are caught in a moment together. This bit is like being caught in the headlights, but you will settle in to it.
For me, the period of adjusting into motherhood/parenthood on the whole took me about 18 months. I found it hard to get my head around my new life. Where nothing was predictable and nothing seemed to work anymore.
Then bits would fall into place. And when they do, they are so undeniably worth it. Think of it as a dessert where you have been walking for mile upon mile upon mile. You crave water. You dream it. You can't believe you will make another step without it. Then someone dribbles a little cool water into your mouth. It gives you hope. You want more. You will find more. You keep going.
Darling, keep going. Break up this next bit. Get your DP to take full responsibilty for house and food over the weekend (and every for the next wee while!). Don't move out of bed except for a shower if you want one. Drink loads and eat well. Latch on babies and watch telly/read/phone/MN/doze.
Apply the 'lazy bastard' method of survival. Routines can be hammered out later.
Keep talking xxxxxx.