Late period negative tests 😩

So my period is late by 4 days & I’ve been testing at least once a day every day with first morning urine all tests come back negative. This is the first time Im late since getting my period back (I got them back in September 2021) since having my son in May 2020 (I was exclusively breastfeeding him) I do still breastfeed but not as often since he’s older now. I had sex last night/early today (it was around 1am lol) with my husband & right after I went to the bathroom & noticed a bit of blood not too much it was light pink/red now it seems to be going away. Idk if this is my period??? Or what m. I don’t usually start my period like this.. I’m just having a big WTF moment 😂