Slowly start weaning your pumping down. Pump off enough that you feel comfortable and gradually that milk supply will taper off. But don't just stop cold turkey. As you found out, you'll find yourself painfully engorged. Just pump off enough that you are comfortable...even if that is only a minute worth of pumping, and you'll stop producing as much milk at that time.

Breast feeding is a total supply and demand relationship. If you've demanded that milk from your body all this time, your body will produce it. Until you stop demanding that much, your body will continue thinking it should produce that much. But if you gradually wean it down, your body will gradually stop producing it, and you won't have the same engorgement issues.

Or you can try cabbage leaves, and stop cold turkey, and your body will just reabsorb that milk after a few days. You may have some engorgement and discomfort for a few days, but the cold from the cabbage leaves will ease some of the swelling and discomfort.