Dreaming of a coffin means that you may have been under a lot of pressure (including emotions) in your life and study recently, almost to the limit. I hope you can find out the reason carefully and adjust it in time.
Of course, recently someone upset you, made you angry and unhappy, so you lost your coffin in your dream, and you even felt anxious and helpless in your dream. Pay attention to traffic safety when traveling.
I usually have this dream when I am in a bad mood or too tired, and I feel the same way. Don't take it to heart, be careful in everything and be patient with others. (Coffins generally refer to villains)