what do you consider implantation bleeding?

haven’t ever really tracked ovulation and conception before this month so i’ve never really paid attention to symptoms and what not. i’m guessing i’m about 10 dpo, took tests on both 8 and 9 dpo they were negative. had some pretty severe on and off cramping yesterday, then later in the afternoon some slight pink color when i wiped. then later in the evening some bright red, and then this morning light brown and now, nothing. i’ve never experienced implantation bleeding before, not sure if that’s what this could be, af scheduled to come around the 15th. anyone have similar experience? not sure what kind of bleeding is considered implantation or about when it should happen.