Tranmission Problem.?

I Have a 1999 Chevrolet Malibu. It has 162900 miles. It starts great and everything seems to work right. But i noticed today when i put my car in Drive it took like 3 Secounds for it to move. Like i press on the gas and nothing. But goes into Reverse just fine. I Bought the car on March 30th. with 158230 and every since i bought it there has been a noise i believe on the driver side. I Bought mabey it was either the Wheel Bearnin or the Tire. I Got a tire rotation and it still makes the noise. And i always then thought it was the wheel bearin. But after this happenin today im thinkin its the tranny. What could be wrong? I Put alittle fluid in there but i can not tell how much i had in the first place cause it has no Tranny Dip stick. Just has the cap on the tranny. So any help would be great. Thanks