Hey Silver,
You might want to invest in a swim safe just as a security blanket of sorts until you get your confidence higher.I almost got one when I decided to enter my first tri which is 6/2.The swim is 800 yards and since I am basically a rock with arms and legs I was apprehensive about any water.I could swim but not with any efficiency.The swim safe is reusable if you have to pull the cord and it would come in handy if there are times when you are alone,even if you are in water you can stand up in. I have done several open water swims now with my partner who is also entered in the tri.She is a dolphin in the water,but she had a little issue last week with being in water where she couldn't see the bottom. She has been open water swimming all her life but she told me it just got on her and she freaked out a bit.We worked on it and she's more at ease with it now.I also will flip over onto my back and use a modified backstroke when I feel tired.You might also want to invest in the book "Total Immersion".It helped my immensely just by showing me how to find my natural buoyancy.With help from my partner and our local high school swim coach,I think I can gut it out.I hope some of this ramble helps you.You can do it!!!!Tammy