OK, it's scary but I've been there, done that and it's OK, really. There's an old thread here discussing it, when I went through it with DD3.
Briefly, I was monitored at 4 weekly intervals with DD3 (ultrasound scans to check that she wasn't anaemic - they do this by looking at the Doppler blood flow through the cerebral artery). I was induced at 40 weeks exactly, as they wanted her out. She was fine at birth but develop HDN (Haemolytic Disease of the Newborn) at 12 hours old and rushed off to SCBU. She had the UV lights above and below her for 5 days but didn't need a blood transfusion. We were discharged from hospital at 7 days, monitored by the paediatricians for another 3 months then discharged from there. That baby is now nearly 4, bright, happy, with no ongoing health problems.
I won't lie - SCBU was scary but the paeds were fabulous. I will never forget looking at her in her little incubator with a drip in her hand, an NG tube and (more amusingly!) a little pair of foam sunbed glasses on to protect her eyes. She had most definitely been Tangoed! I spent all the time I could with her, and the nurses were great at showing me what to do, helping me express milk for her etc.
Also, just to let you know, I had Anti-E antibodies with DD2 too, but the levels didn't get high enough for the medics to be worried about it. She also was born full-term, weighed 8lb 14 oz, and has had no issues from the anti-E.
Good luck, and let me know if there's anything else you'd like to know.