I think what Allan was trying to say (correct me if I'm wrong Allan) is that it's worth whatever someone is willing to pay.
Did you overpay? I don't think so, it's definitely a keeper though. You may find that tomorrow someone is willing to pay $XXX, $XXXX or maybe just $X. You never know... it's all in the eyes of the buyer.
Put it to the back of your mind and portfolio for a year or two, when you come back to it I'm sure it'll be worth more.
Never worry about overpaying, there's always someone willing to pay more, although whether that's now or months/years in the future you never know.