Snorkeling trip to Maldives coming up, but I'm not a strong swimmer. Any advice?

My partner and I booked a trip to the Maldives for our anniversary. I really want to explore the reefs, but I'm not the strongest swimmer and I tend to get tired/anxious when I'm in open water for too long.

Besides wearing a life vest, are there any gadgets or gear that can help me keep up and feel more confident in the water? I just want to enjoy the marine life without feeling exhausted after 10 minutes.