Khloe Kardashian has a message for her haters ... or perhaps this was for ex-boyfriend French Montana?

The 28-year-old reality TV starlet hit the gym in Los Angeles on Thursday, and while she had a smile on her face, her "B*TCH PLEASE" tank made us wonder what kind of a mood she was really in.

Khloe and her rapper beau are "on a break," according to a source for Us Weekly, but a snitch tells Hollywood Life that Khloe had suspicions that French might have been cheating!

"Khloe does not want to come off like the victim in this but there were huge questions about French’s loyalty," an insider told the site. "She just doesn’t believe that he’s faithful to her and she’s not going to stick around to be humiliated, the way she did with Lamar."