You've gotten great advice hear. Cardiac rehab is a great first step. You get the monitoring and education so that you work up slowly and at the end you know what you can do. I am very lucky. My cardiologist is a marathoner and my cardiac rehab exercise specialist is a cyclist. They encourage me to do all that I can and still stay safe and they are very specific about what safe means.
My doc won't give me a stress test. He says the rate of false positives for post MI patients is too high to make it useful without some symptoms during exercise.
Yes, you do get better after rehab. Several of my meds have been cut or stopped. We had a 45 year old come in after a heart attack during a bike race. He recovered and went back to racing. Best of luck with the rehab!