Okay, i am back. I went back at six months after my first and four months after my second out of financial neccessity.
The first tip is like the other have said you will have to accept that there are some things that you just wont have time to clean. I have a cleaner who comes once a fortnight to help out and if i do things in between times thats good but if i dont then its just too bad. Anyone that comes to my house know i am a busy mum and they just have to accept that my house is always messy!! If they are a true friend then they wont care!!
Tip number two, meal planning, i plan our meals at the start of the week, i have a mixture of meals some for when i wont have much time to cook some more elaborate things for the weekend and some meals that i can just do int he oven so i dont have to worry about defrosting the night before.
Tip number three our priority is the kids so they come before everything except for our half our walk just after tea we go for that no matter what so that we get some excercise. One of us is usually with the kids at night playing and the other is getting tea etc. Dishes that cant go in the dishwasher get done at night, my DH does them once i am ready to go to sleep as he gets up a little bit later than me in the morning (he sleeps in my 3 year olds room as she is a difficult sleeper so he waits till i am ready to go to sleep and then goes out and does them before he goes to bed) We structure our day around the kids needs it makes our lives easier and makes for a happier more peaceful home
In the early days i got as much help from family and friends as possible and we didn't do much on my days off just the routine things like shopping etc to stop me from getting too exhausted,
It must seem overwhelming at the moment but the time will fly once you get back to work my DH and i frequently remind each other that in the big scheme of things this time is such a small portion of our lives it seems to make us feel a little bit better.
In terms of getting more sleep i cant help much there my 3 year old still wakes over night, luckily my DH deals with that, when i went back to work after DD2 i was getting up to feed twice a night, i dont know how i did it but i just did, i suppose i knew i had no choice so i just had to get on with it! Now some nights she sleeps through and some nights she wakes once so it is much easier. My only tip would be to get as much sleep as you can even if it means napping during the day!!
It sounds like you have a lot on your plate atm so i would put work to the side and worry about that later. I hope that things with your DH improve soon. You must be very worried.
Take care of yourself