Hello doctor, my son will be 3 years old next month, and since Tuesday night he started with a low fever , yesterday night he started getting 38.3 , and this morning was 39.1. He says he stomach hurts, and when I touch it it seems bloated, then I tap it and makes sound like he has a lot gases, I have been administer him ibuprofen for the fever, nothing else, his mood is normal until he gets high fever. What can this be?