Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.

The best bet is to find a level of activity with which you are comfortable and get your INR adjusted to that. Thereafter be as consistent as possible with your habits.
my activity is still much lower than it was, and that's not sitting well with me. I'll just have to up it slowly, and deal with the INR, as needed.