Parker McCollum abruptly canceled his concert in Pennsylvania on Saturday evening . . . and just walked off the stage.  But he had a good reason.

People at the show say he told the crowd he was sick, and he even threw up about 15 minutes before it started.  He told everyone he was going to try to tough it out, but it was obvious “he didn’t feel well” . . . and at one point, he decided he couldn’t do it anymore.

He said, “I apologize sincerely, I’m going to call the show . . . I’ll give each and every single one of y’all your money back . . . I’ve never done this in all the years I’ve been singing country music . . . I hope you guys will forgive us.”

@jhn925 @parkermccollum #parkermccollum ♬ original sound – Jack