I feel very dizzy.............?

whenever i go to sleep in the afternoon after i have already slept i feel a bit dizzy but yesterday i went to murray bridge and i didnt sleep at all that night, all through the day i was tired and when i got into the car to go back i fell asleep ( i wasnt driving im only 14 ) and when i got home my mum gave me a panedine forte which helped with my headache. but tonight i jsut feel like im going to fall to the floor help please.. and i have had plenty to drink and eat today.