Hello PAC: I see this is your first post here on PC. So... welcome to Psych Central.

You made reference, in your post, to certain things that can't be changed as well as to stupid things you've done in your life. And you wrote you'll never have the courage to talk about these things with your parents & perhaps not even with your therapist. However you didn't mention what the things are (not that you should... that, of course, is up to you.) But it does make it difficult to know what to suggest here. Anyway... here are links to 5 articles, from Psych Central's archives, that (hopefully) may at least be of some help:

When You Feel Absolutely Awful About Yourself—Regularly

When You Feel Worthless

Breaking Free from the Bonds of Badness

How to Stop Punishing Yourself

How to Survive Suicidal Thoughts

I hope you find PC to be of benefit.