Cold chills can come from having the flu, or perhaps in your case with the
fainting, could be something as simple as you not having enough protein to eat on a regular basis. Protein is like the wood in a fire, it burns and heats up a person. And if you ain't got no fire, you'll get cold. In addition, protein gives you energy, and if you don't have any, you can get pretty weak and light-headed. But there are many reasons why this happened to you, those are just my top two choices.