Dont let anyone criticise your parenting skills, a doctor wouldnt be worried for loose stools with no fever for any less than three days. It could be gastroentiritis, when my son had that he was hospitalised within a day and was very, very sick. 13 month olds dont normally cope very well with it, make sure she keeps her fluids down.
If she still has loose motions tomorrow, phone NHS direct, s he may need a stool sample. If you feel she is deteriorating then of course take her to A&E, if needs be. Or even phone nhs direct tonight, they can tell you what you should do.
The main thing with bugs is keeping your child hydrated. I know here in Somerset there has been an awful bug going round. Sounds like she is the victim of something similar.