I don't always feel comfortable recommending this, but one thing that's helped me tremendously with obsessing on the past is low dosage antidepressants. I take 5 mg of Celexa and it has really made a big difference.

I think there are other "stop thought" techniques and mental games to try and control this as well.

Although sometimes the only thing that really helps is time. Good luck!!!

There is no arriving, ever. It is all a continual becoming.