I'm going through this right now. It's actually called ASAD - Adult Separation Anxiety Disorder. Whenever my husband or son are gone for an unspecified amount of time, I panic or suffer extreme anxiety, and the longer they're gone, the worse my anxiety gets. I wasn't so bad with this until we had a fire in December and lost everything. I think that brought it on. My husband gets called out after hours and on weekends occasionally, and I have a really hard time with it when it happens. Or when my son is taken somewhere by my parents and they don't tell me when they'll be back. I've discovered I have some abandonment issues going on, too, which may figure in there somewhere. You may want to explore if you have any abandonment going on from your childhood and also about adult separation anxiety. Many of the suggestions here are good ways to deal with it as it's just another form of anxiety. I find, though, that if I'm just too anxious I can't read or relax at all.