Discharge color

So I've been having discharge for the last 3 or 4 days, mostly light brown, the other day it was light pink and right now it's like a greyish brown.. I have a lot of cm right now, I keep feeling wet down there lol, my period is due in 2 days and I tested yesterday but it was negative. Could this be a sign of pregnancy or just my period on it's way? I have regular cycles and this never happens. I hear grey discharge is a sign of BV but I know it's not because I know what that's like.