Hi Jackie,
Sorry you've gone unanswered, many are busy in other areas and it's hard, for me anyway to remember where I've been.
Anyway - Celexa should be taken in the morning not at night. Best to inform your doctor of the change/reason . If you haven't done so already miss the usual night dose and take it the following morning. Many of the SSRI's will make you alert, no surprise you can't sleep.
hope it's better
Nick