Congratulations on your pregnancy!
Maybe you can change your perspective and focus on different aspects of the vacation. If people start drinking about 5pm, how about taking a long walk on the beach at that time? After dinner, maybe you can play with your child and the other children who are there. I spent a week at a lakeshore cottage with my kids, their spouses and my grand-children and we all had the best time. We focused on the kids and cooking and playing in the water and it was super.