Far be it from me to tell you not to stress where your baby is concerned, especially after the drama that I recently experienced w/my son. When it's our kids, all bets are off. I can tell you, though, that my nephew had the first condition that you mentioned, that of growing too fast, and it was scary for all of us watching him cry but the good news is that he outgrew it, if you'll pardon the pun. Do try not to get yourself too worked up, though, regarding possible outcomes. Easy to say, I know, but take lots of deep breaths and know that all the PTers are praying for you and your son. Keep the faith.