Please think about keep your hair going longer. The weight of the length will help tame it. Or it may be something you will eventually get used to. Since you've been trying to straighten your hair all the time, it'll takes time to adjust. You need to begin by doing your best to get your hair healthy. Just like deep conditioning, gentle shampoo (or "no-poo"), cut down on styling products, etc. The healthier it is the better it will behave. Let your hair air dry most of the way and them smooth aloe vera gel all through it. It helps the curls to take shape and lay smoothly. You will love all above the styling products!
Another option is to have your hair thinned or cut into some style that'll take some of the bulk away. But, I suggest finding a curly hair specialist to do this! They've developed specific techniques for cutting curly hair. Very different from cutting straight hair.
For extremely thick, try giving it some time and trying some different things before getting it thinned or layered. I would use that as a last resort. Ultimately, whatever makes you happiest about your own hair is what is most important.
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