I say it a lot. I say it enough to be considered the stereotypical apologizing Canadian. No joke. I'm sorry to say that I do say sorry far too much. The problem is, I rarely think about it. It's just something that I say and I don't think about it as a feeling, but it is. Sorry has some of it's roots in the word sorrow.
Re-read that above quote. I agree wholeheartedly. It is a waste of time nad energy. Instead of feeling sorry try directing the energy and emotion into something else. Me, I will often exercise to burn off steam. It helps me feel better and not so sorry for myself about whatever that happened that was beyond my control.
Sometimes it's had not to sink into the well of self-pity. And maybe you can't help it, but you can be aware of it. If you're aware that you're sitting there feeling sorry for yourself, then get up and walk out the door. Go for a walk and enjoy nature. Call a friend. Go out dancing. Climb out of the well. That's not you in there - you're a better person than that. Always.