Active cals not tracking

I’ve just bought a FR235, my active cals are way out. For example yesterday I walked just over 10,000 steps and my active cals was 42!!! So over my MBR I apparently burned a grand total of 42 cals!! I’ve checked all my info and settings and everything seems correct. I’m getting so frustrated! As a seasoned runner a Garmin is my perfect watch but atm my Fitbit served me better 
Pls help me!!!