Is it true that ur period stops in water?

is it true that wen u swim your period stops coz im going on hoilday on 27th may and ill b on my period . i am gonna b swimmin every day so i cant just say i dont want 2 go in n also im going with mydad n my younger sister hu has not yet started her period i am also going with my dads girlfriend but im quite shy n wuldnt feel comfortable talkin 2 ny of em. i need 2 use a tampon but i have tried one b4 n it reallly hurt i dont rlli like them but wot other choice have i got. i need some advice and help with wat 2 do and by the way i started my period about3 months ago n im 12 thx