Am I hacked??

Okay look, so a pair days in the past my buddy beginning sending messages on xbox in our group chat UNDER MY NAME.. that I didn’t kind or ship.. AT ALL

Have a look at the image, the messages circled in blue weren’t typed by me in any respect, however they’re nonetheless getting despatched beneath my title. I’m scared and confused. Is my account hacked?? Somebody please clarify to me what’s going on..