swimming with crush and with blood. what do I do???

Okay so my friends and I have planned this day for ages and what we are doing is going to the beach now my flow just started today and mine is usually really heavy on the first day. I can't use a tampon because I've tried and it just hurts me, if I say I can't go the will still make me go and also I really want to go. I haven't gone to the beach in ages and I don't want to miss out on this opportunity.oh and my crush will be there 😳