CGM accuracy needs to improve. When replacing the CGM it needs 24 - 48 hours to calibrate properly and will show higher or lower numbers than usual. Install your CGM when your blood sugar is stable 2 hours or more after your last meal. This will help with calibration. Also sleeping on your arm with the CGM and putting pressure on it will lead to inaccurate readings and warnings. It is just a tool. Keep in mind that the over all trend is what you are looking for. Lower high readings and a tighter range over time means progress. Any unusual spikes or low readings should be checked with a finger stick.