When I traveled overseas and got really jet-lagged (like 13 hours), I took a tablet of melatonin before bedtime and that corrected my sleep pattern within a day or two. It's a hormone your brain releases naturally when you go to sleep so there aren't any serious side effects. Basically you're just suggesting to your brain to release it at a different time.
I'd also skip the caffeine. That stuff stays in your body for a long time. If you get tired, just will yourself to endure it for a day; if you nap, that could throw off the pattern again.
