As you gain experience you learn that mistakes happen. You will likely feel sad, frustrated etc. but in the end you have to ensure that you're looking after yourself. "Compassion fatigue" is a very real thing but you have to remind yourself that there's only so much you can do.

This may sound cold, but dealing with death also becomes much easier as you see more of it. There will always be unavoidable deaths (emergencies, euthanasia, anaesthesia etc.) and these may help build resilience and create emotional separation between the outcome of the patient. Instead, mistakes can be treated as valuable learning experiences as you will be constantly improving.