I'm so sorry to hear what you've been through :( As arohadxb said - only you can determine that. Perhaps you could speak to the NUM and do a day or two on a trial basis prior to starting (or at least visit the NICU) and "test" yourself?
First of all, sorry to hear of your loss, big hugs to you. If I was you I would take the job. I think if it was me it would help me to be able to help others in a similar / same situation. You can empathise with them and offer them honest comfort. I am sure there would be hard times when your loss is highlighted in others' situations and you are sad, but in the long run I think it would be a good, healing thing for you. Best of luck in your decision.