1999 Dodge Intrepid What is wrong with my Car?

Engine Performance problem
1999 Dodge Intrepid 60000 miles

I was driving my car on the expressway all of a sudden my car start slowing down on it on even though my foot was on the accelerator. So the car is still slowing down on its on and I am letting it do that as I am pulling over to get off the streets. As the car is getting slower I am ready to stop so I out my foot on the brake and the brake is locked how it would be if the car is off mind you the car is still in drive gear. So I hit the brake even harder so the car would stop and I but the gear in park. I finally cut the car off and then when I try to restart it it wont start I mean it would make the regular sound but it wont turn over. I notice I dont have any anti freeze in the car I put some in I notice that my oil is low I put some in. After I did that the car started up, so the next I take it to the shop to get a oil change the put new transmission fluid in, anti freeze and the oil change. The car was working okay that day no problems, but the next day it does the same thing the accerlerator goes out and eventually stops and the car wont start, what is wrong with my car?