What does this mean: falling asleep a lot more than usual, constantly staring into space, sleeping randomly?

By staring into space I mean I like stare at the wall for about half an hour and I don't know what's happening. I slept last night for 9 hours. The night before I slept about 5. I feel light headed and irritable. I am 12 years old and this is my 3rd, 14th period as well. The last two have been very heavy. On my first one I fainted in the kitchen for 20 minutes in the morning and I just lay there. Help.....I'm on my period if I havent said that o.O