The technology with which wearables report on stress is not well developed. Take it with a grain of salt. If this has never before but started happening, yes, it could be that something is really happening in your life and triggering a stress response but can also be a glitch. Most likely you are overreacting and there are no causes for concern, but just in case, why don't you go to your GP and ask for the blood panels to check on your heart? Even if your risk is low, it is still a good idea to get bloodwork done at your age as this will establish your baseline, like a benchmark.

I think you are so preoccupied with the idea that you can lose weight fast that the preoccupation alone stresses you out. And if it stresses you out, it can spike your cortisol level which in turn can make it really difficult to lose weight. So most likely, for your own good, you need to relax about your weight and not monitor your calories in and calories out to the last little calorie. After all, you have been doing it for so long lately and it has not worked, so why not re-assess your strategy based on data?

Focus instead of finding ways to move that make you feel joy. You have your VR headset–does not it allow you to select from a wide variety of workouts? Surely there must be something that you simply love doing. and then, success will breed success, as one of my DBT group leaders a long time ago used to say.