My guitar amp feels like its missing the power behind it?

I bought a marshall MG100HFX and I love the amp but it when I play on distortion it sounds like I'm in the next room sort of. So I hooked up my distortion pedal and run that through the clean channel and it sound better but I feel like I'm lacking power, any tips on gettin that umph out of my amp? Like an overdrive pedal or boost pedal or something?