A feeling you get when someone has called your bluff.
When you feel ill and sick to your stomach because you are the cause of a hurtful situation. You try to deny it to yourself but that feeling won't let you.
So, you go shopping with your friend, then go home and talk shit about them to your mate. Then your mate repeats what happened shopping, word for word to another friend and that friend then goes back and tells. BUSTED!! You should have a guilty conscience!