Short of breath elevated d dimer. emerge is sending me home with a shot of heparin and ct in the am. isn't a clot in lungs life threatening? scared

Blood clots: It sounds like you have a complex set of issues and have already had some evaluation. For personal attention to a medical concern, consider a 2nd opinion "inbox consult" with a doctor on HealthTap; it allows you to message back/forth like email when a lot of information needs to be exchanged (like prior test reports, lab results.) Blood clots are indeed serious and easy to miss.