Now that i think about it , when i was quite young , i used to have a dream similar to this . I heard this high pitch noise in my ears , and almost felt this hind of pressure on my head , and for some reason i thought the universe was ending in my dreams , like you said it was collapsing in on itself . I almost felt the universe collapsing in on me . I had this dream quite regularly for a while when i was young , then it just went away . I just ignored them i guess .

No space aliens though .