The average rectified forward current rating is the the maximum average current the diode can handle working as a half-wave rectifier when fed a sinewave at mains frequency (see
this).
Note that the rectifier current peaks at Pi times the average, and then is zero for half a cycle. This is a diferent figure than the maximum DC current the diode can handle. For example, in the
Rohm diode FAQ, under "Most of the parameters specify average rectified current. How much DC current can be supplied?", they provide graphs where you can see that the maximum square wave current (duty cycle = 0.5) is a tiny bit higher than the average rectified forward current, while the maximum DC current is about 50% higher than that. Of course, this might change from diode to diode. Read your datasheet carefully.
Anyway, applying a +50% rule of thumb, if your max average rectified current is 150mA, increasing that by 50% gives 225mA. So using 250mA of DC current might be pushing the diode a bit.