Breastmilk doesn't mean you're pg, it's caused by prolactin, a hormone your body makes, and sometimes if this gets out of whack your body produces breastmilk - I've seen it happen in males, so it's not always a sign of pregnancy! But I do hope it is in your case.

However, it won't hurt to do an HPT in the morning and if you're not pg go and see your GP about it, because high levels of prolactin can mess around with ovulation and TTC.