I am an Equinox person. Fall one in September - the 22nd or so. Never changed sides. At first they lasted a month or six weeks. Then it got to where they lasted till the Spring Equinox. And there was one year where I had surgery and the doctor was not at all helpful with the storm he stirred up in March. Not a Neuro and did not care. That one lasted eight months, not the normal six.
Just keep in mind that they morph over time, They can change for the better or they can change for the worse. If you meant that they began in September rather than November, that fits a common profile. The Equinox.
This mess can change sides and dates too. It just changes on us!
I highly recommend the D3 Regimen!! It really helps a lot of CHer's.