when i put my car in drive it will go to 25mph then it just revs up goes nowhere on 2000 Chevrolet Impala

reverse works 1 2 3 works drive just revs up after 25mph,i changed fluid & filter.My car was running fine parked it for a day,then drove to the hospital going down the road it would not go past 25 without slipping.At a complete stop in drive i stepped down on the gas pedal,went to 45-50 then slipped,the rpms was up in red zone.Can you give me any advice on how to fix this problem,i have no money to get it repaired,i am on disability with four children.I am pretty handy with repairing cars.please help me out,i need my car for emergency reasons.No codes showed up. THANK YOU VERY MUCH

Asked by for the 2000 Chevrolet Impala
Have you re-checked the fluid level since changing it?....Just a starting point.