Whenever I slowly take off I can hear a scraping sound from my rear wheels. I think its my drum brakes. Do you think they need to be re-calibrated?

No -they are probably worn out. Take it in and have the shop look it over, or if you don't mind jacking the back end up and taking the wheel off the drum will come off fairly easily. I had a scraping sound in the rear of my 1994 SLE (CSFiend'* green SLE from the dinner at BWW'*) after I parked it when I got my SSEi. Pulled the drums and sure enough they were worn out. I went and got the mid-grades from NAPA for like $20 -they aren't expensive and for better braking I'd suggest the premium shoes as they are probably no more than $30 if that.