Struggling to feel like I belong in my NICU :/

I got my first RN job in a Level 3 NICU and was THRILLED! I worked with adults for 2.5 years as a PCA and was drained from that population.

I started at the end of June and just came off orientation last week.

The main issue? I feel like I know NOTHING. I was technically thrown off orientation 3 shifts early due to staffing issues. When I spoke up about that to the charge nurse, I was basically told "Well, this is what we have to do."

I haven't caused harm to any of my patients, but I feel like a fish out of the water. Parents are asking me questions about their kids and then I feel like I barely know the answer... I understand what to do & when to do it, but I don't get the 'why' at all. Other nurses have been nice and trying to help me, but some seem to forget that I just graduated in May and all my experience is with adults.

What do I do? I feel clueless. My manager hasn't checked in with me at all to see how I'm doing, neither has our unit educator. I guess they're just assuming I'm fine?