Bleeding 9 days after iui

pi

I had iui last Friday, 7/16. Everything seemed great. On Friday, 7/23, I had light spotting of dark blood, which looked like pictures I saw online of implantation bleeding and obviously I was excited. I started taking estadroil Friday night. Now today, Saturday 7/24 I have had bad cramping all day and there's been brighter red blood. I'm guessing this is my period starting. Do you think there's any chance it might not be? 😬