I just got my first period and I’m freaking out!!

Okay, so I just got my very first period today (6/11) and I’m not exactly sure what to do. I told my mom, and my sister but they really didn’t care. My sister is happy for me “becoming a women” and all, but she really didn’t give much of a thought to it. And I’m over here FREAKING out. Especially since I’m on my moms work trip!! She didn’t bring any pads, tampons, etc. and I have no idea where to get “supplies”. The scary part of all of this is, tomorrow I’m supposed to go tubing for the very first time! And if I’m on my period I don’t want to get blood all in the water, on myself, or on other people around me!! That’s so gross!! So does anyone have any ideas on what I should do when I go tubing tomorrow?? And plus.. I’m really scared on putting a tampon in.. and yeah, I know where my vagina is, I’m not an idiot, but it’ll hurt putting it in, and taking it out. I don’t wanna do it. I’m freaking out!! I don’t know where to get pads or tampons, I don’t know what I’m gonna do when I go tubing tomorrow (because I really don’t wanna miss out on all the fun because of my stupid first period having terrible timing), I’m afraid to tell anyone about it because everyone I know already has their period, and I’m TERRIFIED to put a tampon in.. :( help!!