19 month gap here between DD1 and DTs too madeup - it must be incredibly tough at the moment, it will get better (though realise that feels a long way off). They are now 8 and 7 and brilliant fun - it's great that they're so close in age a lot of the time - many of the same interests/same kind of 'level' at stuff.
The first year was really difficult, if I'm honest. Some things which we did that helped:
threw what money we could at surviving that time on the basis that things would get better. So we had a cleaner, plenty of takeaways, and whatever little luxuries would keep us going. We realised that the first double buggy didn't work for us, so got a second - expensive, but made a big difference to how mobile I was...
went out. Every day. Rain, or shine
Set up the house to make things easier - so we had changing stations with nappies, clothes etc both downstairs and upstairs, ditto toothbrushes. I came downstairs with the kids before OH went to work and mostly we stayed there
Accepted help where offered. Local friends/family gave us food for the freezer, took twins out for naps in buggy etc.
Gave DD1 main meal at lunchtime (DTS had awful colic and had to be carried around constantly for hours in the evening - special mention to my FIL who would come over in a crisis to pace around with him so I could look after the other two)
Will see if I can think of any more. It did feel as though that first year was a survival mission, but it was also a really special time at times and I think my kids (and us) are really lucky to have the family set-up we've got now. And congratulations!