It sounds like Alison is suffering from a form of clinical depression called manic depression or bipolar disorder. One day she is high and on top of the world, bursting with ideas, energy, and the need to do things and make plans. Then suddenly, it all comes crashing down, and her low periods -- where she can barely move and thinks nothing but negative thoughts -- are just as extreme as her highs.

Bipolar disorder is a serious condition that doctors still don't totally understand, but it can be treated. With counseling and medicine, Alison could almost certainly bring her extreme mood swings under control so that she could feel more balanced and no longer at the mercy of her highs and lows.