Nipple leaking?

Not pregnant, although I'm currently TTC. I was sitting down drinking my coffee and noticed that my shirt was soaking wet on my left side. When I peeled away my shirt, my bra was wet around my nipple. I didnt spill anything on myself or lean against anything wet, so my nipple is the only thing that could have gotten my shirt wet. Didnt smell or have color. It reminded me a lot of when I leaked after I had my daughter.

Has anyone had experience with this? Any thoughts on why this might happen? Should I see a doctor?