Help! Should the burn stale of automatic gas from home appliances still smell close to rotten eggs? Every time my heater comes on, which isn't exactly foreign, this horrible...

Every time my heater comes on, which isn't exactly foreign, this horrible smell of rotten eggs fills the full house. We called our AC guy to come check it out since our electric fire runs on natural gas. We hold CO meters set up, but they have never gone sour. He checked the CO levels and didn't find anything, but he did not bring his fluent gas meter so he couldn't check that. Anyway they said that there be no problem. It still concerns me. My family is complaining of runny eyes, itchy throats, dizziness and sleepiness. Is it possible for natural gas to still smell even after its be burned off? Does anyone out nearby have any counsel? It would be greatly appreciated!
Answers:    This odor is Mercaptan. It is the odorant that's added to LP and natural gas for the sake of slickly detecting un-burned gas by smell. What I'm hearing is that you hold a gas leak. Burned gas does not produce this odor.
Get a professional out in that ASAP to find the leak.
You hold a bad problem. Call your gas company emergency number and own them come out. I would also leave the house until they can arrive.