I did 14hour flight, 10 hour stop-over (in which I did not sleep at all because I was too stressed), 5 hour flight, 1 hour stop, 3 hour flight. OH GOD IT WAS AWFUL. The final flight was the only one on which I slept - I think knowing that it was my last flight and that I didn't have to worry about any (more) delays or cancellations allowed me to relax enough to get some sleep. then I had to wake up again...