Exactly how tall are you, what did you weigh when you started, what do you weigh now? Also, how much weight have you gained in the last 6 months?
Like Flip said, calves are generally stubborn and can take time to grow. They also take time to figure out what each person responds best to. Some guys do better with more frequency, hitting them every single workout or even every single day. Some guys do better with more volume, blasting calves hard twice a week.
There are a bunch of calf routines you can try, but the rest of your training is important for context. What does your current week look like? The days, exercises, sets, and reps.
EDIT: Didn't see the above post before I submitted. That figures.