I'm not too learned on this, but our house's CO monitor in the boiler room must of been not working, out of batteries or... something, cos our house was flooded with Carbon Monoxide. No one else was in, and I got back from going out to the mall, and I started feeling pretty dizzy after a while and needed some air, so I went outside, then my mom got back with my sister and she thought the same, but we just thought nothing of it, but my sister lost conciousness, and we felt dizzier and dizzier, so we rushed outside, and called an ambulance. and she's in the emergency room now, and me and my mom have had blood tests, that came back okay, but I'm worried about my sister :S

I was going to take a nap rather than go out... how dangerous is Carbon Monoxide poisoning anyway? Did I get really lucky?