I’m sorry you weren’t adequately supported in your first position. I’d recommend applying to a new grad program again asap. I think you would still qualify. Maybe avoid a specialty for now as you gain experience and confidence. Plus medsurg is usually the easiest to get a position and they’re used to new grads. Just be honest about your previous position and also maybe have a plan for how to be successful during your next position/come up with ways they can support you and see if they can be a good fit.
Perhaps start off at a facility that seperates the critical infants from the more stable NICU patient's. Having more stable patient's may help boost your confidence and also increase your assessment skills since sometimes even stable babies can get sick and need to be transferred to the higher acuity unit. I currently work in the Intermediate NICU, but I will sometimes float to our Advanced NICU and care for their less critical patients. It breaks the monotony of caring for mostly feeder growers but I don't have the anxiety of caring for a patient that has a high chance of decompensation.
First of all if you feel that way, perhaps you could ask for additional training and/or go to another NICU to start over, if that is where you really want to work. Most hospitals could offer you a buddy system where you can work alongside another more experienced RN until you feel confident to work without them. If your past hospital didn't offer additional training, then that hospital is not the place for you. No one should work alone if they don't feel confident yet.
There are also different levels of NICUs, sometimes in the same hospitals and sometimes different hospitals. Perhaps start in a level two.
Dont feel intimidated, it takes a while to become a seasoned nurse. Certainly Don't give up. Knowledge clicks with repeated usage.
Presently, there is a Nursing shortage so Hospitals are looking for nurses. Start looking for positions that will train you/orient you back into the field of your interest. There are many search engines but you can always go straight to Hospital websites and look for what jobs are available if you have a specific place in mind.
If you left on good terms it should not be too much of a problem to get back. It may take a while though. During an interview be honest.