Someone is hoping that whatever has happened, Happens to me next. For example. Someone falls down in the street. '' May your turn come next. '' This person wants me to fall over next.

I puzzled over your question for a while before reading Terrent's answer. I do believe this is a vindictive wish as Terrent implies. I don't know where you came across this, but this person sounds rather malevolent. It seems to mean: This bad thing happened to me, and I hope it befalls you too.