Smaller on the pill?

I recently started on the pill (yasmin) and was prepared for my s getting slightly bigger. Throughout the first month, they definitely were bigger and firmer, yet during my pill-free week they returned to normal and have remained like this even though i am 2 weeks into my second pack of pills. They even seem slightly smaller than before I started the pill! Is this normal and will their size constantly change or stay as it is now?