How did you decide to have baby 2/3/ etc?

So hubby and I have been married 5 years and change and have a beautiful baby girl that is 7 months. A friend asked when we are having another one and I honestly didn't know what to say. But hubs and I talk about it here and there. Don't get me wrong- I love my daughter. She's perfect and smart and pretty much only fusses about hunger, diaper, or being tired.

Honestly I struggle with depression and the first few months kinda sucked. Between her NICU stay (a month- she was struggling to breathe right after birth too so I didn't even get to hold her before she went to the NICU) and then add in hormones, trying to breastfeed (ended up not, for my own sanity) and being severely sleep deprived, I've been teetering on depression since she was born more than I have in years- somewhat also due to other things that have happened this summer. I'm finally on the upswing. I don't know if I can mentally handle it again even though we always said we would have 2 kids.

How did you decide to have another baby?