This can often happen when you take off length. Sometimes the hair has a "freak-out" period after a cut and then will return to normal later. Also, sometimes you will lose curl for a while with shorter hair. I find that getting a really good, slightly layered cut from a stylist who understands curly hair is key. That ended up being the key to my short hair looking its best.
Also, what are your properties? What techniques/products are you currently using?