Very few people on this plane of existence live up to the standard of "good" they hold themselves to. You're setting a very high standard for yourself which is, for a large part, contingent on factors outside of your control. At least this is how I see it. It's not a fair contest. It never was.
Even the few portraits of "good people" we hold in our minds are influenced by mixed motives. It's simply part of the human experience. So give yourself a break. In so much as desiring to be good, you demonstrate that the capacity exists. In feeling genuine remorse for your actions, you have the capacity for good just as much as you do for bad or "evil."
I'm not sure what else to say that can help... but this framing helps me to stop self-flagellating somewhat. We're all only human at the end of the day. Hope it helps. Best of luck.
