I'm heading down to the beach on the 13th and will be there for 3 days. Last month i got my period on the 16th, but my period hasn't been regular for the past two months, varying about 5-7 days. I'm nervous i'll get it during my vacation and I'm not used to tampons. What should i do? I'm willing to try tampons, but how often do i have to change them? My flow isn't that heavy and lasts about 3-4 days. Please help!