Just 2 miles shouldn't be that bad -- not enough time to heat them up and warp the drums.
If you want to make sure you didn't warp anything, drive a few miles to get everything warmed up as usual, then, when approaching a stop sign or light, don't apply the brake pedal, but pull out the emergency brake. If you feel a pulsation while you're slowing, then your rear drums are likely out-of-round. You can get them resurfaced and throw some new shoes on, and that'll work most of the time.
Also, the rear brakes should be self-adjusting, provided they were adjusted properly after you last had them serviced.