Breast leaking... oil?

Erin • TTC 32

Hi everyone. I'm new-ish here. Husband and I have been off birth control for a while but this (December) is the first month we have officially been tracking and trying to get pregnant.

Anyway, yesterday I woke up and my right breast had leaked something oily overnight. It was soaked through my bra and a T-shirt (yeah I sleep in a bra, I know I'm a weirdo). It was enough to scare me, honestly. I've never had any issues with secretions or anything along those lines.

Has this happened to anyone else? I went to my obgyn and she ordered a blood test but she didn't give any indication of what might be happening.

Thanks in advance!

Erin