My hair is severly damaged due to straightening. I've decided to stop straightening it but its uncontrollable!?

I have EXTREMELY curly hair, dry, poofy, frizzy hair. Over the years i've been straightening it with the flat iron. This has only caused my hair even more damage. Since i live in Fl and the humidity rates are very high, i usually flatten my hair every day. I've decided i need to stop if i still wanna have hair by the age of 20. The problem is my hair is very unruly and wild and very very thick. When it is wet i can usually style it by adding hair spray or a product to it, but i just want to stop harmful substances all together. What is something i can do to my hair or put on it to keep it from going wild and be able to go out without looking like a disaster? Thanks :)