Mac Stuck on one volume even if it is set on mute after removing headphones

My Mac is currently stuck at one volume after removing my headphones. I restarted it and tried to put in my headphones again which was fine (even before putting headphones) but when I remove it, it will be stuck on one volume if I play it on the mac speakers. If I mute it theres this icon replacing the bar (something like the circle with a cross) then if I put my headphones in again, I tried increasing volume the icon is still there. Are my headphones broken?