One note about the username: despite what you may have seen in anime, it's not profanity. "Shimatta" is the past tense of "shimau", to finish or end. It has a negative connotation (i.e. "it's done, it can't be undone, (and I wish it hadn't happened/I hand't done it.)"), and can be used as an expletive, but, despite the norms of English, expletives do NOT have to be profanity.
To put it in proper perspective, the words "it is finished," (said by Jesus on the cross), could legitimately be translated as "Shimatta."