My hair is really damaged. i don't know what to do...any suggestions? (: <3?

i curl my hair quite frequently, i have long hair. and its naturally straight. but i wanted to have my hair in a different style so that's when i started to curl it (with straighteners.) Now that my hair is damaged, i never know what hairstyles to do with my hair and how to protect it. i use heat-defense spray, but i don't think it helps really. please help me >.< xx