Please don’t ignore!! very confused.

I had unprotected sex around 3 weeks ago. was supposed to get my period 4 days ago and in place for the past few days I had some brownish reddish spotting that was light instead of my period and it ended today. took two tests yesterday to see, both negative!! I don’t know if it is implantation bleeding or if it counts as a period because it basically stopped today, but I know you usually don’t have implantation bleeding when you’re supposed to have your period. so around a total of 4-5 days of this light brown stuff, some days a little heavier than others but light. I don’t know if the possibility of me being pregnant is high since the tests were negative but i’m confused if that counted as a period? I felt like it was too heavy and dark for implantation bleeding even though it was light... please help!! I also know stress can mess up your period but I don’t know if that counted as one, can periods be super weird like that ?? never had it before. advice ???