dark almost blood like

I've had this very dark brown almost blood like looking thickness but its brown not red coming from my vagina now for two and a half weeks. I was recently diagnosed with endometriosis and was told my periods could take up to a few months to stop. I'm very scared of what the very dark brown almost blood like  stuff is. I know it's not a period but coes out looking like one. it keeps me up half the night wondering what it is and how to make it go away. This is two and a half weeks now. I"m so very scared. I don't know what it is. I know it's not normal that's for sure.

[ticked]

It just means its old blood.  Has it gone away since writing this post?