With a full patient load, why can't I tell what comes first?

You handle one patient well. You see the whole task — what they need, in what order — and you do it without strain. Give you a full assignment and something breaks. That is not your skill failing. That is your sorting failing. Here is what is actually happening: your mind treats every task as equally urgent, because you have not forced it to rank them. The panic is not really "too much to do." It is too much held at once, unsorted, all shouting at the same volume. This can be learned. It is a method, not a personality trait, and you can drill it until it holds under pressure. If the dread follows you home, or you can't shake the feeling that you are failing people who depend on you, say that plainly to a charge nurse, a mentor, or your employee support line. That is not weakness. That is information you need to act on.