North End are without a win in eight npower League One matches after losing 3-0 at home to Doncaster.
Mousinho said: "It wasn't a good day. It seems like a recurring process where we have a few solid results and then we've gone and produced that performance. In terms of the game itself it was bizarre.
"We'd prepared off the back of the Bury game and were looking to get a heavy home win, which we've been lacking recently, but within 30 seconds we were turning around having not defended the corner at all and that set the tone for the whole afternoon.
"Obviously there's big expectation but the best players need to thrive off that pressure but clearly we're not.
"Clearly we are falling short. Eight games without a win at home is poor. We should be making Deepdale a fortress and making it difficult for teams but we're not."