I had some mild cramps followed by a little bit of spotting at the beginning of October and
again a couple of days ago, but definitely not
enough to be considered a period
. I have no other symptoms, I feel perfectly fine.
Right around late August/ early September I also started going to the gym and doing around 4 hours of cardio per week (I had never really exercised regularly before that, and I heard sudden exercise increase can stop periods).