My son is experiencing bloating, gassy stomach, headache and chills. This is the 2nd time this month. He is 24. He started with this 3 weeks ago and vomited every 1/2 hour from 10 PM to 5:30 AM last time. Then felt miserable for 3 days after. Tonight it seems like it's happening again. No idea what is bringing this on. He is miserable. GasX doesn't help, tums don't help, pepto doesn't help. He vomits until he's just throwing up stomach bile. He feels very cold and wants lots of covers. I'm lost about what this is. Any ideas?