Guilt vs Shame
When addressing interpersonal conflict, it is important to communicate clearly to the other party what you are feeling. A prerequisite to doing so is coming to personal understanding of your current emotions.
To this end, I find that distinguishing between guilt and shame often helps. Consider the situation where you have done something horrible. It is likely that you will feel both guilt and shame. Guilt revolves around the horrible action itself: you regret what you have done, and your conscience weighs heavy. Shame, is where you feel bad about yourself (were you always this nasty?).