Could also be monoxide poisoning. Pay $50 to have your furnace inspected, it might have a cracked heat exchanger. They seem like they're working fine-but leak monoxide.
I was not sure where to post this I just need some advice or words of strength my son has been sick bad for two weeks he has been going to the bathroom constently like 5 times in 15 minutes he goes in for a blood test in the morning to see if he his diabetic he has not eaten since 5 and it is 10 and he has a headach that gets worse he had a headach at 6:30 and was complaining his head hurts I know from the past week if i give him food his headache goes away he is not over weight if anything he is on the low end of his weight I was wondering if other parent on the forum have went through this I guess I am scared for him he is 11 years old and it has been hard to see him go through this