Weird jetlag

While in Philadelphia, I tried to keep on French time (to avoid jetlag on my way back) by waking up between 2am and 3am every morning. This worked out quite well (and gave me an additional window for efficient study!). However, since I am back, I have been faced with the weird phenomenon that I wake up at 2:40am every morning and cannot go back to sleep! This is quite annoying and had never occurred previously. Maybe my brain got somehow so wired to this “emergency wake-up call” before 3 that it needs time to erase it!