The Long Weekend

A bickering married couple Peter (James Caviezel) and Carla (Claudia Karvan) go for a weekend getaway with some friends in an effort to blow off steam and work on their marriage. However, their friends never show up and Peter and Clara are left to their own devices. Peter and Clara fight constantly and we later find out why; Clara had an affair with one of their friends and terminated a pregnancy that Peter believed was his.

The whole time they are there, strange things involving nature begin to happen. It freaks Clara out to the point that she steals the car the second night, stranding Peter. She gets lost, going in circles, and eventually crashing. Peter hears noises and fires off his rifle and spear gun. The next morning, he finds out he accidentally killed Clara with the spear gun. Freaked out, he finds the car himself, and tries to leave. Having the same problem, he runs on foot and finally finds civilization. He tries to flag down a passing trucker but a bird flies into the driver's cab, distracting him. Peter gets hit full force with the trucker's vehicle and is splattered on the road.

The final shot of the film is the couple's wedding video, back when they were actually happy.

Thanks Spectre!