But is it possible that they could last for hours and hours? I'm new to the whole panic attack world and I'm really scared. Can panic attacks last for extended periods of time? As I said, I have worked myself into such a mess that I'm convinced that I have a terrible disease. Now I am anticipating having to go to bed and I'm terrified! Even though I'm no longer taking Celexa, I still can't sleep because I can't turn off my mind and the terrible thoughts. Does anyone have any suggestions to calm myself at night. As soon as darkness comes, I start to feel anxious. I feel so lonely and scared.