End to jet lag. In general it takes 1-2 days for every 1 hours time travel. So with a long flight like that, it may take a little time. Things that can help. Avoid caffeine and alcohol. Also make sure in the time zone you are in to entrain your body to that zone right away. Bright natural light first thing in am. In evening when it gets dark, trial of melatonin 3-10 mg adults 18-65. Good luck.