Am I late? Unusual spotting...BFN!

I have had a VERY regular 26 day cycle since I had my Nexplanon removed in May of this year. This is the third cycle that my husband and I have been actively trying.

I got a positive opk on CD15, and based on that, Glow predicts that I ovulated on CD16 (which would make sense if you ovulate 12-36 hours after your LH surge).

I usually begin to spot around CD24 and it gets heavier until AF begins. This month I spotted a little CD23, and then nothing. I also have had heartburn on and off and sore breasts since CD23. Oh, and frequent urination.

Then on CD26/10DPO (Monday of this week) I thought AF was starting a day early. I used the restroom and noticed red/brown when I wiped. I cried, put in a tampon, and figured we’d try again in October. Later when I took the tampon out, there was not much on it. So then started my confusion.

Yesterday was CD27/11DPO (which I don’t normally get to as AF usually starts that day). The same symptoms continued along with off and on nausea accompanying my heartburn. I wore a pad all day, and there was nothing on it. I would only see a little brown/brick red when i wiped. Took a FRER around 4pm—BFN.

Today is CD 28/12DPO. I’m experiencing the exact same symptoms as yesterday. I believe that I would be considered two days late (correct me if I am wrong!) but still only having a little brown/red when I wipe. Nothing drips into the toilet, and my pad is still clean. Took another FRER, and it’s still a BFN.

I’m just confused...is this just an odd cycle for me? I usually have 2 days of spotting leading up to AF and the spotting gets heavier as the day goes on. Day 1 is usually medium flow, day 2 heavy, day 3 medium, day 4 light. I get cramps as well, and although I have felt a few slight crampy feelings, not like my normal AF cramps. This is nothing like a regular cycle for me, but the BFNs are throwing me off! Any insight?