I'd be grateful for any advice:
Took ddog out to the garden this morning. After she'd done her poo (which seemed fine) she spent a good few minutes running around with her back in a strange arched position and her bum tucked under her. She also did a few funny "sits" (unasked) with her bum just hovering over the floor (she's a lurcher and this position is very unnatural for her). I thought maybe she hadn't quite finished her poo so I followed her round a bit more but she didn't try to go again and eventually her posture went back to normal. (She's lying down now so can't really tell but will obviously keep an eye on her).
Any ideas? She's about 8/9 we think (she's a rescue) and has been spayed and seems well in herself otherwise 
N.b. we're on holiday atm and back on Monday.. will obviously take her to the vet if it's still an issue then but would lean towards not taking her this weekend unless it's urgent iyswim.
Thanks