no its not plagerism.you did get it from a source and changed the wording around to make it your own,then this person copied your changed version...so its more like hearsay by this point. I would contact the person and ask what the deal is. And also make it a point on your site that if anyone wants to "borrow" any of your work that they should at least have the courtesy to ask and give you credit for it. But really if they are reporting news that everyone has heard a million times over, who shoul be getting the credit??