Help, Transmission or other?

I have a 1998 Ford V6 automatic transmission Mustang and recently it
stopped moving when in drive. I was driving at 45 mph when i tried to
speed up to pass someone and it seemed that nothing happend so i
pressed harder on the gas and only the rpm went up until the car jerked
and started speeding up. A bit later and i was losing speed and had to pull
into a parking lot where I found i could not go anywhere but in reverse.
Checked the Fluid levels and everything was fine so i tried again and
couldnt get up past 10 mph and had to be towed home. while checking
what could be wrong i got it off the ground and had the gears shifted and
everything looks fine there, wheels would spin when in the proper gear. I
just cant seem the figure out what might be wrong.