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.
Otherwise, there are other things that can cause the symptoms you describe. Pneumonia comes to mind.
If you're really concerned, call your doctor and ask to come in sooner. If they don't have an appointment available, ask to be put on the waiting list.