My first real jet lag was the first time I traveled to Asia and back to the U.S.

I thought jet lag was just a description for feeling tired or having sleep patterns disrupted for a night or two, so wasn't really prepared.

The day after returning, I slogged through work in that tired but still-amped-up way. No problem.

The next day started out OK, maybe a little tired. I went out for a run and just about fainted. I had to sit down while my heart raced, then walked back home. Then later, I was sitting at a friend's house and again almost fainted..just felt really nauseous and lightheaded.

After that, it was fine. I experienced the same thing each subsequent trip, but was prepared...it's always two days after the return for me.