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.
I've actually taken to writing my clotiversary on my calendar because I don't remember the actual date (beyond "end of January sometime"). Not so much so I can think about the bad parts, but more so I can think about how long ago it all was and how far I've come. It can really be a measure of personal growth, which is what it sounds like it has been for you.