I normally take 16 (two boxes) and its about 400 something mg's. I weigh 140 and am 18 - done it since i was 15 once every 4 months or so.. Ive done more, Im sure you'll be ok.
DRINK SOME MILK, and eat something filling.. and regulate body temperature to comfort level.
Lay in bed, and listen to soft music and wait it out...
Or smoke some weed and watch a movie.