Still have breastmilk?????

My daughter is almost 17 months, I haven't breastfed her since she was 3 months old... She was a preemie and she never did latch on my nipples and I wasn't getting hardly anything when I pumped so I had to stop... But it's been 14 months since I've pumped or anything and my breasts still leak milk! Sometimes horribly and other times it's not much. Why am I still producing milk??? What can I do to make it stop? My nipples itch constantly because they are leaking milk... I can't stand it. Sometimes I'll be at work and they will just start leaking. Any advice?