DiveMistress2:I think you fit into the normal set of divers. I'm the same, I wear my drysuit on every dive except when in the pool with students.
You couldn't pay me to actually get wet in open water in our area.
Now the Bahamas is different, I wore a 5mm full when I was there last year and it was 80F (25C). Some of my friends wore their 7mm semi-dry suits.
No matter what you're wearing (unless equipped with Argon) after an hour of bottom time you're going to get chilly.
Whoah! 5mm in the Bahamas is overkill. You might want to consider a full 3mm plus a sleeveless vest underneath if you find you are getting chilly in warmer waters.
Been there, done that... got the vest to prove it!