I have weird old cycles, sometimes they're 33 days, sometimes 37 and every so often I get a 26 day'er 
ttc baby number 2. This month I ovulated on cd23 - it was painful ovulation and I bled afterwards and confirmed with opk... so I geared myself up for a 37 day cycle (luteal phase is roughly 14ish days usually) BUT my bloody AF turned up yesterday at 10dpo. Bright red blood in the morning, no pain.
Since then bleeding has tapered off, have experienced no pain like AF at all (just throbbing in ovaries?) and my boobs are still sore when they usually stop being sore once AF arrives. Like its been so little blood I haven't even had to wear a pad, it only comes out when I wipe.
I also had a random bleed around cd26 which was almost identical to what I'm experiencing now and lasted 2/3 days.
So basically 3 lots of bleeding and rly sore boobs, 0 positive tests, AF massively early.
Any ideas?