I'm rewatching the first season of Bakemonogatari and it still confuses me how Hanekawa (in episode 10) was already known to be possessed by Black Hanekawa. I'm not sure about the timeline of this either, because burial of a roadkill white cat happens during the first season's episode and it doesn't look like it was a flashback moment. It also looks like in that same episode (1 year after the flashback?), the possession symptoms reappear in form of headaches, so I'm confused about when this all happens.
Black Hanekawa says in a flashback "If this stress is not dealt with within a year..." and then she gets suppressed by Shinobu. Does that mean a year has passed?
When does the possession begin and when does that flashback scene happen?
How many repeated possession occurrences are in the anime now?