Traffic can be a scary place. I'd spend some time in retrospection to better understand why this event, at this time, caused a scare significant enough.... that it came home with you. I think most of us that bicycle in traffic [as well as those that drive in traffic] regularly have close calls. Just my guess.... but I'd say most such "scares" are discarded... with the next exhale.

Mirrors are good things. I ride with a mirror. I also ride with the knowledge that cycling most certainly does and will attract ouchies.