Help please😭.

So I’m like 8 days late on my period and this Friday I’m going on my senior trip and we’re going to an amusement park that has a pool. I was ready but i thought of me going into the pool and the whole area around me is going to get red. I’m 13 and I CAN NOT USE TAMPONS AT ALL AND NO MENSTRUAL CUPS NOTHING UP MY VAGINA🤣. Please help me cuz I really want to get into the pool with my friends😭. Can I still use a pad on my underwear and with my swim shorts?