Bachelorette weekend

I need some advice, not sure what I should do. I'm in a wedding in October for a good friend. She has decided to have her bachelorette weekend in mid August and I am due in mid Septmeber. During that weekend I will be 35 weeks. The trip will be to the beach about 4 hours from home. The beach in mid August is hot!! I'm already suffering from swollen feet ankles which my doctor says is normal with me sitting at a desk all day and I'm also having really bad pelvic pressure/pain (Doctor also said this was normal). If I'm already this uncomfortable I can't imagine what it will be like in another 6 weeks. I've left it with I will have to see how I'm feeling when it gets closer to time, but am I a bad person for not wanting to go at all? I feel like I will make everyone else's trip so much less fun! She deserves to have a blast and I think I will slow them down.