Worries, silly worries

So I have 41 days to my big vacation. Where am I going? Did you see The Bachelor this week? That is where I am going! St. Lucia! My cousin is getting married there on April Fools Day. Does that mean it's foolish to get married? Possibly, but hey it turned out well for me so far! Anyway, my best friend and I are heading to the Caribbean for the wedding. Four nights and 5 days. I am extremely excited, yet more and more worried the closer it gets also. Here is what happened that has me so freaked out...
December 23 I spent the afternoon baking muffins and wrapping presents. December 24 I was gone from home about 8 hours. By 6 pm on Christmas Day I dozed off in a crowded room of people, and my husband's family is LOUD. I snuck off and crawled into one of the guest bedrooms at my mother in law's house. I had planned to stay the night anyway, but not to be asleep at 6 p.m. or sleep 16 hours. Obviously I had overdone it. But, I still don't feel as if I did. Baking muffins is the simplest chore ever, Christmas eve I was gone quite a while, but I was just sitting around hanging out, not running around.
My worry is, if this little can wear me out how am I going to be on the trip? The first day is the biggest, I have to be to the airport at 5:30 a.m. We arrive in St. Lucia at 1:30 then once we check in at the resort's desk at the airport we have an hour and a half drive to the resort. By then it will be 3:30. I am praying for time to take a nap then a long shower. That evening is the rehearsal dinner, and the bachelorette party (which I am excited to be cohosting, it's my first!!). So that first day is going to be a long long long one.
The next day, fortunately, we can sleep in the next day and lounge around the pool as the wedding is not until 4.
Friday, we leave at 8 a.m. for an 8 hour tour. The tour is a land & sea tour. We start and end on a catamaran including snorkeling with the fishies.This is going to be a long day. I am so excited about the tour and am praying it is not too much for me. If it is, I am sure I can get a cab back to the resort. But what a disappointment that would be!!
Saturday I think we are going to venture off to the Castries Market, it is 100 years old!! Other than that, Saturday is really going to be another relax by the pool day.
Hopefully fitting "relax" days in between the busy days will help. Does anyone else have any other suggestions?