evelyn1157,
Changing foods can give her an upset stomach too. You might consider gradualy mixing the foods, or if you wish to change foods,
than make sure you SLOWLY add the new
food to her old one to give her
system a chance to get use to it.
If she has diarrha it is better that
she not eat for a day to give her stomach a chance to recoup. Soft stool but not diahrea
I would not feed her a full meal but
small meals and add a little rice. Or cook some ground hamburger and mix it
with a little rice and feed her in small meals.
Just to warn you by changing foods every time she grows bored of it,
You will probably turn her into a picky eater.
I would just find a good quality food and stick to it and add a little bit of people food for taste etc. like a teaspoon of cottage cheese or cooked hamburger etc.

Remember if she acts like she is not feeling well, please do not hesitate to call your vet.

Thinking of her and wishing her well.