I am so confused!

TTC and dates don't add up. My normal cycle is 28-30 days. According to clearblue I ovulate late, this month CD20. When I put the ovulation date into my app this changed my expected period to day 34 of my cycle. Yesterday was day 28 (original expected period) and I had very light pink and brown spotting, this could either be implantation bleeding at 9 dpo or it could be AF on my approximate normal cycle day. I've taken 3 tests, all negative. Don't really have any pregnancy symptoms except extremely tired. Usually my boobs hurt A LOT before AF but they barely hurt now. Any thoughts? Thanks in advance!