Q: When I put it into Drive, it won't barely move, but it will reverse.

I was coming home from work last night and I drove down the street, up a little hill nearby a O'Reillys part store and an Aldi's when my car wouldn't go forward anymore. I let off the gas and slightly pressed it, nothing. I gunned it, and nothing again just a really loud engine rev. I tried to put it in park and turn it off, and then back on and nothing still. I put it into reverse and it drove perfectly fine backwards. I put it in park, put on the emergency brake and then took it off just in case it stuck, it didn't. I had to call the police to tow my vehicle to the nearest Auto Zone. The guy when I called said it sounds like a transmission problem, and thats it. He didn't specify and I know absolutely nothing about cars. Can anyone help me please? I am panicking and don't want to have to get a part or part(s) worth a bunch of money I don't have.

My car has 732000 miles.
My car has an automatic transmission.