4 or 5 weeks - bumpy snorkeling boat?

I am 4 or 5 weeks along and we booked this vacation before finding out I was pregnant. We signed up for a snorkeling tour where I signed a waiver I wasn't pregnant (bc er I wasn't back then). Boat goes through choppy waters and caves, has snorkeling, trampoline, and water slide. I've heard stories of bumpy boats causing miscarriages during this stage and getting nervous. What would you do? Would you go? Would you have your husband go without you?