We felt this way when started thinking about number 2, and also the other big one was can we love another baby as much as we love our first (highly irrational but we loved DD1 so much we didnt see how it was possible to love another as much as we loved her)
but it was all good.
as soon as we were pregnant the love started flowing and when she was born it was just the same as DD1.
it hasnt been easy, the newborn stage was easier than where she's at now with not sleeping and teething, u do get frustrated and angry and short with ur other child, but u quickly make up for it.
DD2 slipped so easily into our lives that it was like she'd been here forever.
its hard when ur sick, but luckily we have family close by who's more than willing to take the day off to look after DD1 while i recouperate.

Cant be all that bad, we're already trying for number 3