no I didn't mean sleep with them in same bed xander and willow just like in house as friends not loversShe was wanted by the police. (Even if charges of murder were dropped, she still assaulted police officers so they'd still be after her, and even if she wasn't wanted, they'd want to ask her questions that she couldn't answer without getting herself into more trouble.) Buffy's mother also told her to leave.
The only place I could see her staying is with Giles, and the police would likely look for her there thanks to Snyder.
Her heart was utterly broken, and as far as she's concerned, she just did worse than kill someone who meant everything to her. Most people aren't going to to feel better through sex after that. I expect even Faith wouldn't be comforted, though she might seek it out anyway (but Buffy is not Faith).
In case it needs to be said, love and lust are very different things. You can lust for people you hate, let alone don't love. (Granted, Joss and Marti both seemed to find this a difficult concept to understand, at least to put into a story.) You can love others without feeling any sort of lust.
Xander and Willow were firmly in the latter camp of people she loved but did not feel lust for.
And trying to think, but Buffy has never been into casual sex. Not even season 6 counts as casual sex (even if it was, it was years away after significant life changes.)
On top of that, there'd be the emotional trauma of what happened when she had sex with Angel (as the old saying goes, a cat that jumps on a hot burner won't jump on another, nor a cold one, either). That is, on a gut level she'd fear what happened with Angel (turning evil, death following, then sending him or her to hell) would happen again. Not until she processed it. Plus, abandonment issues which all of this would aggravate.
In any case, she'd need time to deal. She couldn't with anyone there, nor were there hotlines to call (even if they were, it wouldn't mean they're any good).