How do I live with the weight of sentencing decisions?

You can follow the guidelines. What haunts you is the space between them, where the rules run out and a real human life waits on your judgment. That weight is not a sign you are struggling. It is a sign you understand exactly what you are holding. The judges and decision-makers worth trusting are the ones the stakes still reach. The day it stops haunting you is the day to worry. Your discomfort is your conscience doing its work, keeping you careful, keeping you human in a role that could easily go cold. You cannot carry these choices perfectly, only honestly. So build a way to set the weight down after the decision is made. Talk it through with someone you trust, in confidence, or write out your reasoning and let the page hold it. You are meant to feel it. You are not meant to be crushed by it.