Jamaica is soooo much fun. I went to Negril though. I was Pre celiac then.....came home with the big D for 1 month and had Celiac.
You should be able to find plenty of gluten free items there. Bring your own breakfast "carb" and eat the plentiful fresh fruit. I ate a lot of seafood, lobster, shrimp....we stayed at a resort and they were VERY nice. I am sure they would let you read the labels. Jerk seasoning should be gluten-free BUT some use a paste and it says Natural Flavoring, this always scares me....since Dannon Yourt got me

If you can go horse back riding in the mountains. Was the best way to see how the locals live. Our guide even climbed a mango tree and pick us fresh mangos to eat on the ride. You will probibly come back feeling better than when you left

Have fun
Shannon