I'm suffering from White Guilt, reading about the slaves and Indians.?

I've been doing a lot of reading and watching documentaries about when the Europeans came to North America, and I have become so depressed. In America we are taught we are the best, we have the highest morals, we can do no wrong... But it is all settling in that we had slaves for hundreds of years, and that what we did to the Native Americans is (to me) just as bad as what the Nazi's did to the Jews during WWII! We stole land from them, kept pushing them further and further west, broke almost every treaty we made, and when they didn't move we burned their villages, slaughter their women and children in cold-blood (Wounded Knee), etc. I feel dirty, and have been depressed lately, not really proud to be "American" anymore. Like learning that the house you live in was stolen from other people by your Great Grandparents, who killed them when they wouldn't leave. We are always taught genocide was the worst thing ever, and all the focus is on the Germans, but like I said, we did it ourselves! The more I read, the more I come to realize that North America was close to a paradise, and the people were living as one with the earth. Sure, they had tribal conflicts, but no disease, no alcohol... and we ruined it all and built Wal-Marts all over the place. And I look and see the condition of the Native Americans today....I want to kill myself, it's so sick. What can I do, as an individual, as penance for my forefathers sins? Volunteer at a reservation? Sponsor an Indian child to a good school? At least the African Americans are accepted into society, but the Indians?