Ever had what you thought was a period and still be pregnant?

I started spotting yesterday. It was pink and brown. I was 12 dpo yesterday with my period starting supposed to be tomorrow. I’m very regular and never spot. So I thought it was implantation bleeding. It was a little heavier and darker this morning so I thought it was just my period but it’s gotten really light and then heavier all day. Trying to wait until Sunday to take a test. Just curious if anyone had more than spotting with IB or if this is just AF.