Looking for a title for a sci-fi/horror camping movie

I saw this movie and really liked it and now I can't find it anywhere. It starts out with a group of 20 somethings who are going camping in the woods. As they begin, one of the couples has a fight, and the girl leaves them to go stay at a hotel in town. As these movies go, the remaining members of the group get lost and strange things start happening. They find their tent poles up in the trees and think something is messing with them. The group finally realizes they have been walking in a circle and that someone seems to be following them. The "aliens" have the capability to cause humans to hallucinate, and the various members of the group start to hallucinate happy scenes (i guess meant to subdue them) of having a picnic by the lake and swimming in the water. Two of the campers (a male and a female) realize it's a hallucination and run away to escape. They run until they eventually come to a highway where their phones start to "wake up" and all the messages that had been sent to them while they were in the woods start popping up. They are all messages that the earth is being taken/has been taken over by "aliens" and the two realize that while they were in the woods the entire world had been taken over. It ends there, I think.