You are very fortunate to have found a meaningful career that you are passionate about that also allows you help others so directly. It sounds like you are struggling with the demands of your work setting and not the overall nature of your work or career path. In that respect, you are one of the fortunate few. Still, the demands of your emergency-oriented position clearly detract from the quality of your family life in some ways. There are no easy answers to this dilemma but I can share a few ideas.
Many health-care professions are highly demanding and the level of stress and demand is strongly correlated with the type of setting and the types of patients or clients you are serving. Some people find a professional “home” in the area of emergency medicine and this is their path for life. Many others find that they enjoy and thrive on high-stress, high-demand positions during one phase of their career, but are eager to shift settings or jobs when the emotional, physical and family “costs” of these positions begin to outweigh the position’s benefits.
Even though your husband and son are supportive, it sounds like you as an individual might be longing for more uninterrupted time with your family. Guilt is not the answer, but it is a useful communication from yourself that it may be time to consider a change in employment within your profession. Achieving a healthy life balance is a matter of listening to yourself and be willing to embrace change. There are many other positions in nursing and some might be better suited to your personal life and family needs. I suggest giving yourself plenty of time to explore alternative career options in your field and to make the changes in a planned and systematic way. Using this approach you are most likely to find the job fit that allows for greater life balance.