I caught covid in March and it hit my cardiovascular system. EKG signals indicated possible previous heart attacks. I had a nuclear stress test that ruled them out as artifacts (no damage, just how my heart is wired). If you haven't had a stress test for verification, you can even get one without the treadmill/bike part. I've had autoimmune diseases starting more than 30 years ago. It is a challenge to find things and friends to escape with. Covid and autoimmune diseases are very isolating.