Heavy Bleeding

Christine • Officer in the USAF, momma of two trying for number three, engaged to the love of my life.
Hello ladies! I have a quick question. I had heavy bright red bleeding for one day. Enough for a tampon and now I have brown spotting. Does anyone know what that could be? I got 9 days of high fertility with my Clearblue digital opk and the app says I O'd two days before the bleeding started. Thanks for your help!