Did you experience light dark brown discharge before receiving a BFP?

Last month I completely gave up on ttc. Plus, I was sick with a cold the majority of the month so I wasn't obsessing over sex on fertile days ovulation predictors vitamins etc... but today I noticed a brown discharge coming from vagina when I wipe. I've been nausea, but I'm always nausea around period time. I vomited one night after mexican, but I had been drinking too, so I dismissed as being drunk. According to my trackers this would be implantation time. Could this be IB? My period due on the 10th