Ay anak, parang may migraine ka or flu symptoms yan, lalo na kung kasama ang nausea at back of head pain, kailangan mo talaga mag-check sa doctor para sure kung ano ang dahilan, baka may dehydration or something else na kailangan i-address agad. In the meantime, try to rest in a dark, quiet space, drink water slowly (kahit kaunti lang at intervals), at take paracetamol if okay lang sa'yo, a few of my mum friends swear by a cool compress sa forehead din when they're having these episodes.