Hoilday + period

Hi I'm Sarah, has anyone got any help for me cause I don't know what to do?
I am 15 and I get really anxious about my period because it is so irregular. I am going away to Majorca at the end of the week and my period should come on that same day . I don't know how to use a tampon so this means that I can not swim which is upsetting me.y
What shall I do ??