Prediki's trading interface shows your unrealised profit and loss in credits. This is the difference between the amount of credits originally invested in the answer options and the valuation of your investment at current market prices (mark-to-market).
You can either cash-in and realise this difference by closing out all of your investments in a prediction question ("squaring your position") or you can simply take notice of the current status and speculate to realise more winnings (or lose your investment) if you wait for the final outcome of a question.