pack some midol & a heating pad. also get a makeup-type bag to store your pads/tampons in.
if you are goinggoinggoing at camp all day & can't get to your cabin every 4-6 hours to change your pad, i'd recommend wearing a tampon (6-8 hours). also that way if you go swimming in a lake or kayaking or something you won't have to worry about it as much.
good luck.