I have a 19mth gap between my first two (all those years ago now ) but I from what I do remember it was a case of "I have to do this, there is no point wondering the hows"

My DS14 wasnt overly fussed or put out when his brother arrived so that certainly made things alot easier.
We bought him a bed a few months before DS13 arrived and started off with daysleeps in it and slowly over time progressed to full time so no need for another cot. We had a sling I used for the first few weeks until I found a double pram I liked.

Lots of stuff was eased up on until I had some kind of routine down ie housework, washing, trips out, social life - love life! And that was just my personal routine I didnt bother trying to get the boys into one. The rules kept changing so I just went with the flow for a long time as I found that was the best way for me.

As a survivor I can say it is not going to be a piece of cake but you can do it!