Dart,Charging system

Today while trying to start my car my foot slipped off break while pushing the button and my car didn't start so while still in run position. I mashed break to start the car and it did start but once I turned car off when I got to my destination it wouldn't start. Got a boost started right up but now every time I turn off I need a boost what's wrong

My car has 67767 miles.
My car has an automatic transmission.