Self-diagnosis is generally wrong so you need to see your doctor for a proper diagnosis. Maybe there is nothing wrong, or it could be some temporary problem that only your doc can fix with medication.
Definitely tell your parents and get looked at. It is your health and embarrassment is temporary so is not as important as health which can be permanent. Do you have access to a school nurse or doctor or a teacher who can take you to one if you want to avoid your parents?