What went wrong?

Hi!

So I fast a couple years ago, about 5 days and it was great! drank a lot of water with salt and everything was ok.

I wanted to do it again, so I started yesterday (monday) at 8:00 AM, same thing, drank a lot of water and all that jazz.

Tueday at 10:00 I started to get a little bit dizzy and a couple of minutes later I throw up like a white foam.

So of course I stopped the fasting, drank a lot of water eat a boiled egg and called it a day.

So what went wrong? I'm no expert but I've been watching a lot of educational videos and experiences and had no clue that something like this could happen.

Google said that was " accumulation of gastric juices and saliva or air in an empty stomach"

Has this happened to anyone before?

PD: English is not my first language so sorry for spelling.