If something's troubling you, write it on a piece of paper, then seal it in an envelope. This is the conclusion of research conducted at the University of Singapore Business School. Participants were asked to write about a recent decision which they regretted, then half of them handed in their papers as they were, while the other half sealed their papers in envelopes first - then handed them in. The envelope sealers reported feeling less negative about the event than the non-sealers did.
While I can think of factors which might have muddled the findings (maybe those who sealed their envelopes worried less that their regrets were going to be pored over by the experimenter?) the basic principle seems sound, and you could possibly even add to the effect by destroying or discarding the envelope. Definitely worth a try.