I'm leaking!

So last night I was laying in bed and I had my arm crossed over my chest covering my nipple. I changed positions, and when I removed my arm, I felt it was wet! So I looked at it and it was dripping down my arm. I touched my nipple and it was wet also, secreting drops of liquid. It was definitely thicker, like milky texture, but sort of brownish maybe? Wasn't clear. I am almost 20 weeks pregnant.

Anyone else have this or know what it could be inferring?

Ps, like maybe an hour and half or so probably before I noticed this, my bf did nibble on that nipple (lol) but I'm sure nothing was there until way later