First, congratulations!!
I had an unplanned c-section when my daughter was born, and my milk didn't fully come in until the 9th day after delivery.
It does sound like you're producing milk, since (as pp's said) your LO is giving you both wet and poopy diapers.
My LO's poopy diapers were also greenish at first, then got more yellow and seedy after a few days.
I was really anxious for my milk to come in (which probably didn't help ) and my LC told me to just keep nursing as frequently as possible and the baby would bring up the supply as needed.
It also doesn't hurt to drink plenty of water and/or try Mother's Milk tea (from Whole Foods.)
Since my milk came in (7 1/2 months ago) I've never gotten engorged at all - and also never felt letdown, but my LO has gained plenty of weight and is doing well!
I say just keep an eye on your LO's output and weight gain, and you'll be able to tell if things are going well.
You're doing great!