I think you need to speak to your DH. BTW, the idea that he has to go back to work because all these unreasonable people want their New Year dinner, millions of people are back at work this week. Even if he is doing a 12 hour day (which would be uncommon I would’ve thought), doesn’t he start really early and finish relatively early? If he’s home by, say, 6, give him half an hour to shower/have a beer/whatever, and then hand over the children.
At this point, you can go and crash for an hour yourself, have a bath, go for a walk, whatever gives you energy. If you’re lucky, maybe he could (perish the thought), do everything with them til they are asleep, apart from any breast feeding of course, and THEN, you give yourself the hour a pp mentioned to blitz something.
Start with the fridge. Seriously, one hour and you’ll have it back to normal. Not necessarily cleaned from top to bottom, but you’ll be able to see what you’ve got. If you have any decent leftovers, then that’s dinner tonight.
Then, buggies, car seats, potty etc. - do you have a porch, back yard, lean-to, car, anywhere you can put them from the moment you get home in the afternoon (well, maybe not the potty!). Just getting them out of the house is very helpful.
Followed with just normal cardboard boxes, if that’s all you’ve got, and fill them with toys. Keep out 6-10 that your 2 yr old loves, and seriously, a small piece of sellotape to close each box, and stack them up against a wall. If your 2 yr old is always following your around, give them something to do which is similar to you - a cardboard box to fill.
Put some catches on doors so they can’t empty cupboards - you can get them at pound shops.
Music. For you not them! Even the radio, but something loud/bouncy, not magic fm.
but pp has the right idea 1 thing a night - 1 hour a night. If by some miracle you have a moment of calm during hte day, have a cup of coffee and do another 15 minutes.
Good luck, and if you feel overwhelmed for much longer, maybe go to the GP (maybe make that appt today, so it’s there if you need it next week). They can help you know whether it’s just having two small kids, and it being hard, or if it’s depression.