Sorry about reposting but no one is answering..Was he making fun of me?

My ex bf switched into my cl. We don't get along at all. We can't even speak to each other. Anyway, my crush is in that cl too and he's friends with my ex bf. My crush used to look at me all the time but not that my ex-bf is in that cl he hardly ever looks at me. And when we were having a rehearsal practice as I was half walking/jogging away to get something, my crush said, "Don't slip and fall on your ***." and my ex bf started laughing hysterically really loud and for along time. My crush has that kind of humor-He's sarcastic but I'm not sure he meant for me to hear it. Was he making fun of me? And why doesn't he look at me anymore?