Upset tummy advice

[Beamur]

My mature but not elderly dog seems a bit off with a tummy upset. I suspect her food is not agreeing with her, but she has a touch of diarrhoea and was sick a couple of days ago.
She's still quite bright, eating some food (have stopped giving her the food I think could be to blame) drinking, etc. But poo still a bit loose.
Is there anything I can give her to settle her tummy? I don't think a vets trip is needed just yet. Switched to this food on vets advice as previous food was causing constipation. She is quite an anxious dog and vet suggested a low allergy food in case she was a bit itchy (she chews her feet but has been checked for mites). Chewing seems to be a nervous habit. I've only had her for the last 2 years and she's not had the best start in life.

The vet told me to give chicken and rice, small portions. This works on my dog.

If it is the food then giving something to settle the stomach won't help unless you change the food.

Mine didn't handle chicken and rice well but done well with scrambled egg.

My dog gets loose poo when stressed especially after firework night and NYE.

She did have a bit of unexplained diarrhea and we gave her pro-kolin which you can buy online. Coconut oil may also help with the itching but start off with small amounts

Thanks for your advice.
I have swapped her back to a food she has had before and she's eating happily and seems much perkier.
She is quite an anxious dog and I wonder if maybe the change in routines and additional people in the house over Christmas have stressed her.
Things are back to normal now and she's curled up in her bed looking contented.