Spotting

Sa

Okay so I have been having very light pink/brown spotting for the past 5 days. Mostly just when I wipe but a drop or two gets on my panty liner. I have very irregular periods. I'm on cd90 as of right now. I've taken many pregnancy tests most recent one was this morning and they have been negative. (I'm using the easy@home test idk if they're good or not. ) but has anyone ever experienced this or know what it could be???