Keep occupied
My suggestion is to keep occupied while away to avoid getting down and lonely. Changing a lot of timezones and having a disrupted sleeping pattern can cause depression - you can buy a supplement from Boots (or any chemist I think) called Melatonin which helps regulate the body clock and mood. Its legal and from various studies apparently quite safe. I've used it to get my body clock reset and I've always felt better after a good night asleep.