Yes, walk her and no, I wouldn't be taking her to the vet yet.
Put a dollop of pro biotic in her meals, and wait another 24 hours. Obv, if she deteriorates in that time, definitely straight to the vet, but it is more likely, as she's eaten today and it's still inside her, she is improving.
I'd give her a couple of gentle walks a day, half portions of food with a pro biotic added and see what happens.
I also suspect she is just plain tired which will be contributing to it - being away from home and lots of racing about is bound to make her a bit flat and knackered now she's back - especially if she's not been eating/foods been flying through her.
I'd give her a bit more time before rushing to line the vets pockets!
I would say you have to consider where you live daisy. For example, if you live around Stratford-upon-Avon, vets are advising bringing in any dogs with these symptoms following a spate of dogs deteriorating after being walked in a particular area, with the main suspect for a cause being dirty/standing water.
I'm usually with you on watching and waiting and trying some probiotics with stomach/d&v stuff, but am being a lot more cautious recently, after a spate of nasty illnesses doing the rounds. Better safe than sorry and I'd rather give the vet a few quid for nothing than leave it too late and regret it.
I'm with moosemama, some things like cuts and grazes, limps etc, I do home first aid and watch and wait as much as possible. But there have been some horrible illnesses lately, I would take an off colour/very out of sorts dog to the vets quite swiftly.
If my lab was off his food - its never happened yet - I'd be seriously worried. Interesting about the D&V bugs this year, both my dogs have got diarrhoea, but not the usual tummy upset that's over in a few days, its been a week on and off. Weird explosive morning poos that take dogs by surprise, we've had poomagaden in the utility room a couple of mornings . Once they've fully evacuated themselves they're fine for the rest of the day and don't do any more. Still v active and enthusiastic about food. Never taken them to vet with tummy upsets before but will be going tomorrow and bringing poo specimens.