Cepheus having fever

this morning, and we let him skip school today.  His temperature this morning was 37.8.. and just now at 6pm i measured again is an average of 38.5... i am getting so worried.. but now that we just fed him some paracetemol, it is down back under 38 again as he is not feeling as warm as before.. Cepheus have nothing to eat for the entire day and only down two servings of milk (cannot even finish 150ml each time).. we made him some oatmeal at night and he managed to down only half a bowl.. it pains me to see him not eating anything the entire day and the whole day keep fidgeting and getting irritated easily. My MIL said that while we were at work, Cepheus have been crying and have to be carried for most of the times unless he is sleeping, but he will be waking up very soon even after he have slept.. Mommy so xim tia to hear this.. i tried to carry him to sayang him just now, but due to my big tummy, very quickly i suffered backache from carrying him for too long and Cepheus wasnt very happy :(.. finally i managed to carry him to sleep in my arms.. and he is now sound asleep on his bed.. but we were expecting him to wake up soon as he is easily irritated and cannot sleep for long now.. i am wondering was it teething or was it some viral infection that causes the fever.. Aiyan advises that if his fever would not go down and keep persisting at 38 to 39 degrees tomorrow, we should bring him to a PD soon, as paracetemol may not be effective for fever above 39 and we should be asking for ibufen instead.. Cepheus condition is up and down.. when he take in paracetemol, his fever will subside for awhile but once the medication is over like 5 hours later, it would act up again.. this makes me worried and we will need to really monitor his situation at night ensuring that he doesnt get overheated..