Period questionn??!?!?

okay i had my first period on febuary 28th then again on may 18th and i should of gotten it yesterday but i didnt. im only having one sign..i just had a break out of like 7 pimples on my fore head and also im still having discharge(ive had this for like a year,no different) but anyway im going on vacation to turks and caicos in like 10 days on the 29th and im soooo scared im gonna have it. i didnt tell my mom and im not gonna ( dont tell me she knows and she can help cause im NOT telling herr!!!!!!) so do you think i will have it while im at turks and caicos or no because that will ruin my whole vaca. i know how to use tampons but i cant sneak them in the hotel. and is there any way too prevent my period.? im gonna try to loose weight cause i heard that can make it stop so any ways to loose weight in like 10 days? im currently 13 years old 5 foot and like 107 pounds. im a level 9 gymnast and i have lots of muscle so i dont even know why i got my period yet? whateverrr oh and does masturbation have anything to do with periods? thanksss <3333=]