Name of movie

Does anyone know the name of the a movie about someone who got drugged at a party and on the drive home thought someone was after them and pulled over and ran into the woods. It's based on a true story and he or she called 911 and was describing things, and mistakenly thought they were by their house but didn't make any sense. One scene he/she saw field of "workers" but they wouldn't respond, turned out they were cows.