What Causes A Delayed Menstrual Period?

Hi. My period is 7 days late, a first for me. I'm 35 and TTC however I had my progesterone level, prolactin and TSH levels checked. Results were progesterone .24, prolactin 12.5 and TSH .42. I am also steroid dependent as I have Crohn's Disease and have been on prednisone (currently 20 mg every other day) for over 13 years. Could I possibly have hyperthyroidism?