I just found a facebook comment on my gf's wall asking of she has broke up with me yet?

so im in high school and me and my girl friend were able to finally go on a date (her parents approved finally) so we take a picture together and we both make it our profile pic. so the next day its a pic of her and another guy together at a movie theater and i asked her about it and she said that they were just friends hangin out. So i understand and then a few days later i find a comment by the same guy in the photo on her wall that said "So have you broke up yet?" and then she replied "you idiot this is public!" and he was all like "oh yeah shh" and they never deleted the comments. I feel so torn. I feel kinda dumb because i should have figured before this with all of the clues. i don't know what to do.