Tranny Problem?

I have a 97 Camry with 105,000 miles on it. I have had my car looked over at several places recently when getting minor maintenance and they all said it was in great shape. Then I took it in for an oil change and had everything looked over again and all was fine. I get the car back and I noticed the gear shifter slid easy when just the day before it shifted just fine. I drove to work and when I went to get in it to go home, and put it in drive nothing happened nor any other gears. It revs fine, but goes nowhere. I have not had any transmission problems at all nor anything that would indicate a problem. I am hoping for the best but preparing for the worst.