[bryal]

Also, get a new smoke detector just to verify that you're not sleeping every night in a room with a carbon monoxide leak.

[rsanek]

In addition, see if you can start sleeping with your window open overnight. Even if you don't have CO, if you're sleeping in a small room with a closed door and windows, your CO2 concentration will be really high.

[mclouts91]

You mean, get a CO detector. Smoke detectors won’t help.