Implantation bleeding or period help!!!

[Daniandgaz2010]

Hi guys me and partner been trying for a while now I do have irregular periods I have the period tracker apps I have not had a period since beginning of July my ovulation date was the 6th October me and partner had sex 7th October 20th October starting to get spotting was dark brown then went pinkish then back to dark brown had this for three days had no cramps did have a bit of backache not much tho but on the app says period was due 23rd so was this a period it did not feel like one or was it implantation bleeding very stuck and need help or advice thank you x X