The way that your guitar amp sounds in a room is much different than the way that the amp will record through a microphone. this is because your hearing the amp often times from standing above the amp while tweaking your settings.
If available, try putting the cabinet in a seperate room than your head, and keep the head near you while tracking. that way you can tweak the settings after the signal is being recorded, and the changes your making are based on how the mic hears the amp, not how you hear it from above.
if this is not an option, try listening to your amp with your ear directly in front of the speaker you plan to mic. DO THIS CAREFULLY AT SOMEWHAT LOW VOLUME. this is a way of tweaking your amp so that you are hearing it the way that the microphone will.
hope this helps