Advice?

Chelsea
My periods nearly 4 days late, I've been spotting yesterday well I peed and when I wiped I noticed a slight tinge of pink. So I did a preg test it came up negative, today I noticed the same thing except I wore a panty liner and when I had a shower in the afternoon I noticed a browner spot on it so I did another test and it came up negative again. Any idea what's going on could I be pregnant? Please any advice!