The timer within you that makes you feel awake during the daytime and sleepy at bedtime really exists. Anyone who has suffered from jet lag can attest to it, including this writer at this moment.
Yesterday I flew from France to the eastern United States. Against headwinds, the flight took 9 hours to cross the Atlantic and traverse 6 time zones. You may have experienced some mild effects from your internal timer when the switch was made recently to daylight time and you had to get up an hour earlier than your body was accustomed. (Incidentally, the change from what the French call "winter time" to "summer time" is made in Europe a week before it is in the States).
It is, of course, proportionately harder to fly across multiple time zones and then have to adjust to local time. The resultant disturbance in body rhythms equals jet lag (or what the French call decalage). The general rule is that it takes one day to adjust for each one-hour time zone crossed.
Since I crossed 6 time zones to fly yesterday from Paris to Atlanta, that means my body will be out of kilter for 6 days, nearly a week, before I am fully readjusted to local time.
I am taking melatonin to try to curtail my jet lag but I will tell you one thing, I still feel a great deal of jet lag today.
The quickest way for me to recover from jet lag may just be for me to fly back to Paris today.