PleaseHelpAbout Period...10PointsBest Answer!?

okay,im off swimming tomorrow,for competition,and my period will be 5days tomorrow,i cant put a tampon UP because im scared,ive tried itt before and i can't do it,but iff i dont go my dad will be mad att me:( ,my periods a brownish coulor and hardly anys coming out,do you think i will finish forr tomorrow ,but if i don't what should i do?!thanks xxx im 13btw