its happened like four times now. I'll be driving and the car will just shut off but sometimes if im hitting the gas itll start back up but sometimes i have to stp the car and put it in park and then usually itll start again right off the bat, but its the car my pregnant girlfriend is driving so i need help figuring out with whats wrong

 

Have you had the OBD codes read. If not take it to a major auto parts store and and have them read the codes. Write them down and post the codes. It will help in troubleshooting.
It is hard to tell with the information provided what could be going on.