awww big hugs!! Your bubs is 18 days old?  At that age I did whatever I needed to to get through the day sane lol, and I only had one other one at home!  I agree, forget the housework!  Hope the rest of your day goes ok!

Go easy on yourself. 

So what if the house is a mess, who's going to know?  I'd leave the housework till wednesday and try and relax and enjoy your time (I know easier said than done).

A few years ago when there were major floods in the north island I was stuck at home in my teeny tiny 2 bedroom townhouse with 2 toddlers.  I didn't have a car either and couldn't have gone far anyway because of all the blocked roads in the region.  What initially seemed a pretty daunting task (entertaining 2 kids with cabin fever) actually turned out to be heaps of fun. 

We used the dining chairs to make a train and went on pretend trips.  We made play huts with the chairs, boxes and sheets.  At morning and afternoon tea time I'd prepare fruit and set up a shop and the kids had to come and 'buy' food from me.

The minute the rain stopped (even briefly) we'd wrap up warmly, pop our gumboots and parkas on and go for a quick trip around the block before the rain started again.

We read heaps of stories and the kids did lots of colouring in.

You could also do some baking with the kids (or just get them to ice some plain biscuits).

I don't envy you, you must be very tired with your nb too but forget the housework, sleep when you can and when the older two want to play have fun too.