Testing of the heart isn't usually done by blood tests, you also would usually need stress tests and such. But I'm guessing your doctor doesn't see any symptoms of it. Nobody can ever guarantee they've correctly diagnosed you -- certainty just doesn't exist in this world, and especially not in medicine. But if you are anxious, you will feel anxious, and if you're feeling anxious about things to the degree your life is disrupted, you have an anxiety problem whether or not you have a heart problem, which you probably don't. Have you seen a therapist who specializes in anxiety who can help you diagnose your mental state?
In all likelihood you are physically fine. You seem to be suffering from health anxiety. You're 33, so your heart is almost certainly fine. And your tests came back good. Consider getting some therapy to help you overcome your health anxiety. In the meantime, trust your doctor and the test results. Worrying about your health will not make you healthier!