Am I overreacting?

So I just got a call with no caller ID from a girl saying that they just say my boyfriend at a park smoking with a girl. And she told me to keep him on check & be glad she told me. I asked for her name cause she sounded so familiar & she said don't worry about it just be glad I'm telling you alright? And she told me exactly what park & everything. I have no idea what to do. I was with him like 2 hours ago we went with my little sister to panda & idk whether to believe it or not. My heart is like beating so fast. Idk what to do 😫😔😤😤