RN stands for registered nurse. RNs are very different from LPNs. The amount of schooling and education is longer for an RN. RNs usually go through two to four year programs at community colleges and universities. They graduate with a BSN (Bachelor's of Science In Nursing) or an ADN (Associate's Degree In Nursing).
It is important to understand what causes it in your home so you can protect your family from the dangers of carbon monoxide poisoning. Never unplug or remove the battery to silence a CO detector or CO alarm. You may go back to sleep and suffer the deadly consequences of carbon monoxide poisoning. At the very least, ventilate the area and change the detector's battery. Always assume the worst for your own safety.
If you have mold it's going to be very difficult to find, and you may have to call in a professional. Being as it is winter, another, scarier option could be carbon monoxide in your house, if you have a gas heater. 15% Carbon Monoxide in the air can cause mild headaches, and 25% severe headaches and nausea.