I don't think you should feel bad! I would just tell her: "Hey.. I was running out of the only med that keeps me stable, with terrible fear of withdrawals, and NO one told me you were out of town! I've called, I've emailed, I tried everything to find you. So I'm glad you finally responded and have agreed to keep our agreement to keep the scripts refilled, but it would have helped if you, or someone, had told me you were out of the country and when you would be back so that I didn't have to spend so much time afraid out of my mind."