How long until I will stop supplying?

My son will be 1 and a half in a couple of weeks. We had a great breastfeeding journey, but he has finally stopped nursing at night...YAY for better sleep for us! I'm currently still using the mini pill to finish out this months cycle (I didn't want to risk losing my supply if he wasn't ready to stop) and will switch to seasoniq which is what I was using before I became pregnant in a couple of weeks. However, it's been almost a week since he has nursed and there is no decrease in my supply. I'm hand expressing to keep from becoming engorged. About how long should it take before I will naturally stop producing?