When i woke up, i had an extreme stomach ache. then i just fainted and my body felt so cold, i was breathing so hardly. what can it be?

It can be multitude: for best dx saw your dr. however if it passed in 5-10 mins could be vasovagal

Seek help: There are many possible conditions that could cause such severe pain in that area. Some include pancreatitis, gallstones, stomach problems, etc..Instead of making an exhaustive list of possibilities I would strongly recommend that you get this evaluated at your local emergency department. I wish you the best of luck. !

Have pain assessed: It is likely your abdominal pain caused your other symptoms. Severe pain may cause blacking out. It also sounds like you were hyperventilating which may also cause you to be light headed. Often these episodes make you feel hot and sweaty. I am not sure why you became cold. See your doctor to assess the cause of your pain and related symptoms.