implantation? af? i need help

i need help! I'm four days late and I've never been late before so I already got my hopes up. but all my tests have been negative. I finally noticed something when I went to the bathroom, I wiped and there was a brownish color with a tiiiiny bit of pink. wiped again and there was barely anything, one more just to see and there was the smallest little clot. I don't know if af is going to show up or if it could be implantation. this would be baby #1 so I don't know what I'm looking for, I just need help