Mr. Lapsus said:

What I think:
[SPOILER] She is sick. She forgot the coffee and the car. It's all her imagintation. [/SPOILER]
[SPOILER] The alien asking her to forget is a symbol of the treatment she is getting. The alien ask her to remember the very moment his son has born. "Doctor" want's her to remember his died born son, but she can't. She begins to reinvent her son begining whith the real memory of she been pregnant. [/SPOILER]
[SPOILER] At the end, everybody but her is there with their memory erased. Why she is the only who remember everything? Because it's all her imagination. [/SPOILER]
And there's more. And there are some "but" too.