Shift into drive and press on the gas and car barely moves?

The car starts up with no problem! When put into reverse it takes a little bit for the gear to engage! Shift into drive and press on the gas and car barely moves at all! If press the gas pedal all the way to floor engine just revs up but does go forward! Gently press on the gas pedal then the car slowly starts going. However, it will not shift gears stays in low gear where it revs and stays around 4-5,000 RPMs! Now about an hour and half ago my car overheated on me and would not start up right away! Has oil had water and coolant in radiator no major oil leaks anywhere no leaking from the radiator or hoses or thermostat or water pump! Have recently changed transmission fluid, motor oil, and antifreeze coolant! Ready to give up but don't want to just yet so can you guys help please?