First get your thermometer checked for accuracy.
When ever you measure the temperature, wait for atleast 2 to 3 min and then read the temperature.
If it is fever
, along with crankiness, loose stools, low appetite- may be a viral illness.
How is her activity?
What is the duration of illness?
You may give her Acetaminophen
syrup in recommended doses if temperature is more than 100`F.
If she continues to be unwell, have a word with your pediatrician
Give her plenty of water, soups etc. If she has persistent loose stools, try to avoid fruit juices.
Hope you find my answer useful.