Period at the WORST possible time in the world!?

Ah okay so in my high school, if you miss more than 5 days per semester, you have to do various jobs during the summer. Since i missed five more than i should have, i have to go to volunteer with like homeless people. its a four night five day thing, and ill be sleeping over at the shelter. i'm going with three other guys and my female english teacher (who is like 24ish) and low and behold.. i got my period today. (ive had it before haaha) but its not really a place where i can keep tampons on me (we can only bring two shirts & one pair of shorts and pajamas) and i dont think the bathrooms are like secluded? if that makes sense. i go tomorrow.. and i dont know what to do! should i talk to my teacher? thank you all so much!