What Could Cause Mucus In Stool And A Briefly Positive Occult Blood Test After A Bronchial Infection?

Before ten days I had an infection in my bronchial tubes , after three days of the infection I had a diarrhoea with mucus , I went to the laboratory occult blood test was positive and nothing else was seen , in the same day I repeated the test it was negative please help me I am horrified.