hun... couldn't read and not reply.
I think what your feeling is common, a friend of mine had her little boy quite early (can't remember now) and he was in hosp in melb, there were days she had to go home (2hrs+) and she felt horrible.
She told me it was the WORST time of her life, she felt she wasn't connecting with him, like she was failing him and that she felt as though he wasn't really 'hers'.
She has now taken him home and the bond they share is probably that little more special... she's seen him through the hard times, given all her love and effort to make sure he had every chance of getting out of hospital.

Your doing an amazing job... can i just say i think it was great she took photos of her DS, like most parents she had photos from when her DD was born and i think having photos (no matter how hard) of those first moments was a good reminder for her that she did care enough, she WANTED pictures of him to show when he's older exactly the fight they fought together.