Deployments can be especially hard on the parents of service members. Yet, despite the fear of losing one's child in wartime, much is expected of the parent. Your service member needs you to be strong.
This can be emotionally exhausting. It's essential that you acknowledge your feelings and honor them. Create a space for expressing them, either to trusted friends or through writing or some other means of expression. Eating well and getting enough sleep are also essential to combating the effects that this chronic stress will have on your body.
You may be so focused on being strong for your service member and, if they are married, helping his or her spouse or children, that you forget to take care of yourself. Please remember that they are going to need you throughout the deployment as well as when they return and readjusts to life at home, whether that includes transition to the civilian sector or remaining on active duty.
This is a marathon, not a sprint. You will need to tend to yourself and your own needs as well as the needs of others.