HELP advice please. 6 days late, spotting, BFN.

I’m 6 days late but have been spotting light pink/brown blood off and on for the last 2-3 days, sometimes there’s even a little bit of dark red too. It’s a very small amount only when I wipe. I keep testing and keep getting BFN. Has anyone else went through something similar and still ended up pregnant? I have NEVER spotted before a period, ever. So this is very unusual for me and before I started spotting I was VERY crampy for about a week and a half which is also not normal for me before a period. I don’t know what’s going on would just like some insight from someone who possibly has gone through the same thing?