Hair problem with frizzing?

So I wash my hair every two days or so and I always blow dry it and put some anti frizz stuff in it. When I blow dry my hair it's all perfectly straight and fine but as the day goes on half of my hair gets curly and wavy and all crazy looking. No matter what i do it gets like that and when it's even a bit humid my hair just poofs up and curls....is there anything you I could do to take care of this problem and keep it straight.