How do I know if I'll get better or if I'm just not cut out for nursing?

I'm a baby nurse, just 2 years old, but low-key I feel like a new grad who knows nothing.

A bit of my history:

• 1 year & 3 months as a new grad on a Neuro PCU (considered a critical care unit at the hospital). I was bullied and taught from a place of fear while working here -3 months in CVICU (same hospital), but felt like I didn't get proper training (was told I only needed 15 shifts to learn to be on my own because I'm an "experienced nurse.") I left because I felt unsafe and shortened training seemed to be a pattern based off what other RNs said. -6 months in a medical/surgical ICU at a new hospital (current job)

I think/thought I messed up big time with a patient. I had an EVD (this is the 2nd time I've had one since being on my own, 3rd since being in this hospital) and asked for help with zeroing it since I couldn't remember. It was explained to me and I 100% thought I understood, zeroed the machine, and went about my night. My ICPs matched the previous shift (2-8mmHg), no Neuro changes, no output from the drain that had been put to 20mmHg halfway during the previous shift. I looked it up and read that no output at 20mmHg was a good thing, so I went about my night.

Next shift comes on and the RN zeros the EVD differently from me (but leveled it with the jaw and not the tragus) and the ICP is reading 26 and he gets a little bit of output. I'm PANICKING because this is a VERY experienced nurse (who mentioned that getting zero output could mean the drain is clogged) and I'm thinking I messed up and missed something HUGE. I was confident I leveled it right because we did leveling on the Neuro PCU with our lumbar drains, but never had EVDs there or a need to zero it, so I'm thrown. The RN reassures me that he's not gonna throw me to the wolves but that he does have to (obviously and understandably) report it to the surgeon, but it's good that my patient didn't have any Neuro changes. He tries to not make me feel bad, but I'm thinking about the harm I might've caused by messing this up and how much trouble I'm going to be in and I'm horrible for not knowing or recognizing that something was wrong. I felt like I got to caught up in all the tasks, running between rooms all night trying to put out mini fires, that I missed big important things.

He called me while I was driving home to tell me that he rechecked and the ICP came down to 14, so he didn't need to report it afterall and that I was fine. But it just brings up so much doubt: -I feel I have a terrible memory and can't remember things I try to study/learn for work -I'm not good at thinking critically -I can't keep up with the tasks my patients need and end up dropping the ball on one or both of my patients in one way or another (I had my poor patient sitting in her own urine for 1.5 hours while I tried to get her another IV because it was accidentally pulled out, control my other patient's blood pressure, do rounds, check my disorganized orders, check labs, and put in orders). Part of this is that the hospital has nurses doing other people's jobs, but still... -I miss things (like my patient didn't have an order for a BMP..sometimes the phlebotomists will catch it before they draw and ask if we want those labs, but some just draw what's there and go about their way without checking in with the nurse)... so that's another poke for her -I feel like I don't understand what's happening and I'm just doing tasks and going through the motions of things I know I'm supposed to do. Other nurses are able to provide so much knowledge behind why certain things are happening and I'm just reacting to problems instead of understanding them.

Sorry I'm rambling because I'm tired and stressed, but this event just triggered all my self-doubt and I just wanna call out and never go back and find someone who will just care for me the rest of my life so I don't have to work because I suck at everything.

Do I truly suck? Am I really bad? Or is this just growing pains?