Welcome to our merry band of Xen takers. Have you had a look at the two threads "Help for New starters" yet? If you look through some of the other threads you'll find lots of helpful information.
It normally takes 3 days for Xenical to get into your system so it may just be coincidence that you're having these effects. What have you been eating? Is it high in fat, or did you have some high fat foods just before starting which mean the Xen so your body is having a bit of a clear out?
Everyone's different in what they can & can't eat while taking Xen and avoiding Mr Tango, if you stick to the two rules - no more than 5g of fat per 100g of the food (regardless of the portion size) and no more than 15g of fat per meal you should be fine.