a hairy situation

Hello y'all. I'm 20 weeks along and before I started this journey my hair was about to my shoulder blades. Thanks to prenatal vitamins and those good ol pregnancy hormones my hair is now well on its way to the small of my back. I dont want to cut it  but the tangles are getting bad from my tossing and turning at night. I am currently putting it in a lose braid. However I'm fearful of damage even with a lose braid plus it leaves it wavey. I was hoping for some other suggestions on how to secure my hair to keep the tangles away. I wouldn't mind curls in my hair but the braid waves make me feel like I belong in the 70s or something. Thanks in advance.