Hey just thought I'd share my experience.
I've also had colostrum out of both nipples, esp when squeezed but sometimes a good drop or two would leak out onto my shirt.
This coincidentally happened the same time I had my first chemical pregnancy.
I had never previously been pregnant before this happened.
I went to the doctors and had my prolactin levels checked to rule out a benign brain tumor in the pituitary gland (it's not as bad as it sounds; just would need to take a pill each day) - luckily all was okay for me, but that also left me with NO answers.
I still have this today, in both breasts, and have never had a pregnancy beyond 7weeks. I've had this before BFP and before AF, so definitely not a sign for me.
I hope it is a sign for you! Either way though I'd suggest you get your prolactin levels checked, but chances are it's just a normal thing. It's actually quite common (even on BnB) and can actually happen in guys and infants! It's called something like gallorectia or something like that if you'd like to research it.