Why are my curls less curly than before?

My hair is usually 3a but lately it has really been lacking volume, feeling more thin than usual and not being curly. I have high porosity hair that needs a lot of protein, so I'm pretty sure that this isn't protein overload. My hair feels soft, but not over moisturized. I do have a fair amount of protein in my hair products and I use a weekly DC with protein. What is happening to my hair, I'm pretty sure this isn't because of aging because I'm still pretty young.