You may find yourself with less of an appetite than normal. Also the fruits are fantastic, don't miss out on those. There are sometimes vendors along the street as well as the 'market' a few streets from the round-about.

Take-out food is cheaper than a sit-down restaurant (and they may have tables & chairs too). If you are staying where I think you are, there are a couple cook shops nearby, and several on your way to town. These can save you time as well as money over purchasing and cooking 'meat' meals yourself. Seems like the best selection is earlier in the afternoon rather than late in the day.

Perhaps some of your fellow hostelers will go in on cooking a meal with you, as well as hanging out, going to the beach, etc.. Also ask your host for suggestions.

If you go to bars during their Happy Hour, you can enjoy yourself without blowing your budget. Its really nice to get out and relax somewhere other than where you are staying. Happy Hour varies between the bars and their drink specials, plenty of info on this site about that. And a good idea to have rum and mixers at your place too.