some people talk about there being 2 types of SSRI - activating and sedating ones.
Cipralex is a sedating so some say if you take it at night it might help you sleep a bit better, but I'm not sure if their is any evidence to support that but you can try and see how it goes. It doesn't matter what time of the day you take it.
Try to stick it out. They generally say side-effects will be for a week or so and the first few days are the worst - that's why psych meds are hard to start because you get the side effects in the beginning before anything beneficial happens so you feel like you are taking a pill to make you sick.
some people who seem to be sensitive to drugs start taking a lower dose - a quarter of a tablet and work up from there, it may help side effects but does take longer to get to an effective dose. Whatever you decide to do, make sure you tell your dr exactly what's happened/what you did when you see him.

I like wikipedia for looking up stuff, so check this out

http://en.wikipedia.org/wiki/Cipralex

there are also lots of links to other SSRI info - and the intro talks about how it is one of the most selective SSRIs