I dreamed that many dragonflies crawled on me: dragonflies generally symbolize the troubles I can't get rid of, or represent negative thoughts, inner fears and some kind of interference. Being killed, there are many, representing intractable problems, or things or ideas that are difficult to get rid of. My mother helped me catch it, which also means that my relatives have always supported and helped you.
This dream reminds us to cultivate positive thoughts, and also indicates that problems will be solved. Good luck!