Extremely dark discharge (no pic)

My period is due in 5 days. Last Friday, I saw a dark discharge and I thought implantation bleeding. Today Sunday, that discharge is darker and a bit more (but not a lot like period) but it is almost like black-brown, and thick. I do not even think it's IB anymore. Anybody knows what this could be or has experienced this? 

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors