I have a strategy which has been working well for the past about 1 1/2 years now it is producing a maximum drawdown that I have not seen in my testing in the past 5 years of back testing data. Added to it, it is also seeing maximum number of consecutive trades that are in a loss. How do we determine whether a strategy has stopped working? It may also be possible that this is just a new maximum drawdown and eventually the strategy would start performing. In general, how do we find out whether it is time to discard a strategy or to modify parameters?