Monitors&Alarms

Courtney • FTM preterm labor at 25 weeks. DOB 8/19/15 at 32w2d.She was in the NICU for 1m3d. She's now 17 months old!
Anyone who has had to be in the NICU knows how stressful all the monitoring and constant alarming can be. Today, I had my first real scare. My daughter has had some apnea and reflux, so her O2 sat drops occasionally..but she always pulls herself out of it without having to be stimulated. I've been really lucky with that. However, today she was being a little fussy (first time I've ever seen her act that way) and was flailing around a little bit. Then, she just stopped and was laying completely still. Two seconds later, her monitor starts going off with a different alarm than I've ever heard. It was the heart rate and it said 0. It was going off for a while without the nurse coming in, so I reached in her isolette and squeezed her arm. No change. So I went around to the side so I could see her face, and then noticed that she had pulled the monitor off her chest. I must say, that was a huge moment of panic for me. Plus, the nurse NEVER came in. It was going off for nearly a minute before I was able to get the monitor to stick back on her skin and pick her heartrate back up. I'm glad it wasn't a real emergency. I've heard stories about NICU moms having trouble once the baby comes home because all of the sudden there is nothing really keeping up with the baby except for the mom. 
Has anyone else on here gone through this? What about the post-NICU phase of constant worry?