Is this normal after circumcision?

Baby got circumcised yesterday. We were told to put Vaseline petroleum jelly on gauze (enough for no dry spots on the gauze) and everytime when changing his diaper the gauze is yellow, not like soaked in yellow but it has yellow on it.. Is that normal or what?? Please help a worried momma :( 😭 *not urine.. his diaper has the line that changes color if he pees