Struggling with Mental Health and Deployment

I’ve been to the hospital many, many times in the last few months. I’m finally getting answers, but super worried for the future. My biggest supporter, my fiancé, is likely to be deployed soon. I struggle immensely with seasonal affective disorder and really don’t know what to do/how to handle myself without his support. I have a service dog who helps me with daily tasks and syncope alerts, but I’m really struggling with the idea of my mental health and my fiancé being gone for a long time. I don’t feel like my medication is doing anything either and I’ve been on it for about 3 months now.