diarrhea in 3 year old

So today while out shopping my DD looks at me in the middle of the store and yells I have to go poo poo NOW daddy. We are finally on our first really good week of potty training so DH rushed her to bathroom and quickly texts me that he needs my assistance. She had some for lack of a better word skid marks but pure liquid. She was hysterical over having this accident. We tried to calm her and told her it was ok that accidents happen. I asked if her tummy hurt and she said no. We got her cleaned up and went on with our day. A few hours later at home the same exact thing happened. Little bit in her panties except when I put her on the potty this time just tons more diarrhea. Another hour goes by she is in the bath and the same thing. Just diarrhea everywhere. She just ate dinner and is refusing to eat anything off the BRAT diet. Its almost bedtime is there anything I can give her to help with this? She is so upset from these "accidents" its breaking my heart.