my 5 year old grandson says he feels weird (thats all he says) when he says this his eyes turn glossy and red just around the outer part of his eyes (looks like hes about to cry), he turns pale looking.  It only last for maybe 30 seconds then hes fine (color and eyes normal)  Can not link it to lack of sleep, exhaustion - it hits him at different times of the day.  Sometimes he will go 3 - 4 days with nothing
This might be what is called absence attacks. It is a form of fits, and the child would just look strange for a few seconds, and then be all right. He needs to be seen by a neurologist urgently.