Calories way too high

The watch was making sense for the first 6 months. But lately the calorie counter is adding way too many calories. I'll wake up at 7am and it says I've already burned 900 calories. My average heart rate while sleeping is around 65. 

It's glitching some days tell me I'm burning 4k+ a day when I have no activities, no high heart rates, and low step counts (4-5k). If I go for a walk with 10k steps that adds 3k calories to my day bringing me to 4900k for a day. My heart rate doesn't go above 120 during the day. 

If I was really burning that many calories I'd be losing weight. I'm 175lbs 5'10. max heart is 181. I've checked all the settings I know of and have reset it several times, but can't figure out how to fix the calorie count. 

Thanks for any help!