Lactating...?

Hello, I breastfed my son for about 7weeks, but ended up having to stop cause my birth control dried me up..its been about 5(?)weeks since I've been completely dry now, and just tonight my boobs kinda started to hurt and I noticed my tank top had a little wet spot and I looked and I didn't see myself leaking but I kept feeling it, so I squeezed my boob, and stuff came out. It was in the dark, and looked clear-ish. WHY is this happening?!?