First. Learn and apply this favorite message of truckers and bikers (pretty much the same guys):
Gas, Grass, or Ass - Nobody Rides for Free!
Cars - last time I checked at least, and for all the ones I've ever had, run on gas not friendship.
If a woman is willing to share a bed with a guy and sex is not on the table then she really respects you - that's the way I think of it at least. It is frustrating though, no doubt about that. But to the degree that your thinking "Gee is she into me at all?" and she is willing to share her bed with you - then the answer is not NO, but HELL NO. Two people do not share a bed w/o sex being on the table, unless one of them is really set against it. In this case, since it wasn't you, then it must be her.
Of course I think of it as 'respect' because that way I get to keep some of that 'respect' for myself, because the other way it could be is that she's playing you as a chump, and there ain't no self-respect in Chumpville.
and its impossible to say no
Really? Try using this word: "No." If you feel you must elaborate (and I don't know why anyone would need to explain why they couldn't do someone a continuing favor at the drop of a hat) just tell her you have a hot date, have to meet you mom, or the ever popular standby: I can't, something has just come up. Tell you you would but you have to go out to Good Vibrations and pick up sex toys and some new porn. That always works for me. Either they say "Ewwwwww" or they want to go along, in which case you're In Like Flynn.
I barely slept last night, ended up just lying there next to her, super aware of the fact that she was so close, and basically driving myself crazy.
ProTip: You get up, go to the bathroom, spank the monkey and go back to bed and fall asleep. And hey, just so you get something out of it, might as well masturbate while fantasizing about her. (It' s OK, she probably doesn't do those things anyway)