I have the same problem! My friends joke that I am the epiphany of a vampire. I haven't seen the sun now in almost two weeks. I try the same things you've mentioned, trying to stay up all day to get my schedule back on track and it'll work for a while but then I'll slowly fall right back into the old pattern, or HAVE to change back because I'll become so exhausted that I DO feel like the living dead.
I know it's some kind of sleeping disorder because nothing I have tried has helped.