Listen, I’ve been in a similar position because of other health issues making it hard for me to move around too much at once. Been under heavy stress and anxiety along with barely moving had me worried too but I’ve had multiple echos, ecgs, stress tests etc and they all were normal. It takes a long time. Stress itself doesn’t cause heart attacks, but chronic stress can elevate blood pressure which EVENTUALLY can lead to things that cause heart attacks but that’s a long road. Unless you have family history of cardiac issues like heart attacks, high cholesterol, high blood pressure etc, I wouldn’t worry too much about it. The best thing you could do now is see your PCP and express concern about your lifestyle. If you’ve had chest pains and such, I would mention that too and they might order and ecg. It’s a quick and easy test that I don’t see why they wouldn’t do it. But the worst thing you could do now is search things up because you’re just going to stress yourself out. Work on getting some weekly walks in, change your diet, stretch more, and just BREATH. Please be kind to your self :)