I don't have CF, but I got 12 weeks paid leave -- combination of sick leave and vacation. Half that time was spent in the NICU while DS recovered from surgery due to meconium illeus.
But basically it just took a few weeks to get the routine down -- feedings, sleeping, diaper changes, bathing... Also took about two weeks for the swelling to go down. I retained a LOT of fluid after ds was born. And don't get me started about those darned episiotomy stitches <img src="i/expressions/face-icon-small-smile.gif" border="0">