Bombarded With Hate Messages After Injury

Raheem Mostert was engulfed by hate messages from fans after the NFL star suffered an injury Sunday ... with the RB's wife saying people said the Niners player "should kill himself."

Devon Mostert spelled it all out in an emotional social media post hours after the 49ers beat the Detroit Lions ... saying she and her hubby received "THOUSANDS" of terrible comments following the game.

In her post, Devon said some of the messages suggested Mostert be cut from the team ... while others made fun of his injury history.

"I know I shouldn't care, but wow. Wow wow wow," Devon said. "The nasty things some of you just carelessly say is gut wrenching. I don't think ya'll get it. Football is my husband's…