Pretty sure it's a BFN :( spotting/irregular TMI

I've had irregular cycles since my one shot of depro a year ago and after my MC 3 months ago.. it changed from 28-34 days. Day 28 this month I started spotting/light light bleeding no flow at all just pink/brown/light red changing back and forth but not coming out leaving tampon marked but dry and uncomfortable to takeout not like my regular bleed at all which is heavy heavy. Only had cramps first two days again without a flow. 
Held urine all day and get this BFN guess it's just a werid cycle for me :(