BFN 9DPO & 11DPO then BFP?

Katie

I’m 12 DPO and tested negative on 9 and 11 dpo. My boobs have been so sore since 6 dpo and I’ve been having some periodic cramps for the last few days with the tiniest bit of brown discharge when I wipe. I’m wondering if I’m out this month and if not, when should I retest?