Hello Doctor, My Child Is 4 Years Old Shy One

Hello Doctor,

My child is 4 years old shy one month of her 5th birthday. She has been sick for the past few days with a cough, fever and stuffy nose. She has also just moved her bowels after 3 days and I noticed white tissue looking stuff with her stool. She is not the best eater and I did give her a stool softener to help her go which did help to break the fever. What is this stuff and should I be worried?

Please advise. Thank you!