What caused me to feel so sick ?

So today me and my family had a flight to go on vacation. And I randomly felt lightheaded and nauseous when we were going to the airport.

I tried to eat stuff to help my lightheadedness but being nauseous, it was hard to eat anything.

I was so upset having to go on a flight feeling this way.

I made it to our hotel and I was able to eat some stuff so I feel better but now I have a bad headache.

Does anyone know what could have caused all of that? It was so random.