So I'm thinking that what might have happened is that my follicles got overconditioned over time, making the hair easy to rip out. Besides the lighter conditioner I used to co-wash, I also started adding my heavier RO higher up on my canopy to combat canopy frizz. I would also plop, which means that the well-conditioned hair would be smushed near my scalp until set. Before I started cowashing, I would only put my RO on my hair starting at the ears... so I can see how it is possible that my scalp could have been getting overconditioned.
Excessive Shedding: Could Co-Washing Be the Culprit? | hairscapades
This poster believes she had a similar experience. My hair is also fine like the poster.
I've also been researching pre-waxing techniques, and many sites suggest that softened follicles let up hair more easily.
"Softer hair follicles release hair more easily; to make your waxing experience both pleasant and productive try exfoliating and then moisturizing prior to the event. First, exfoliate the area you want to remove hair from, then smooth on some type of non-comedogenic (non-clogging) moisturizer to soften hair follicles and the surrounding skin." Discovery Health "What's the best way to prepare skin for waxing?"
When I was reading about co-washing before I started I read that you had to be very thorough and massage the scalp very well in order to cleanse effectively. Being very paranoid about the possibility of buildup, I massaged vigorously. Maybe too well.
I never experienced buildup on the scalp. It was always clean, never oily, gunky, smelly or anything unpleasant. This supports the possibility that I was over-massaging as opposed to under-massaging.
Since I've been scrunching and styling my hair curly, I've also been experiencing more tangles, which means showers meant more time detangling. Generally I was gentle in detangling, but I wasn't always perfect, and yes more hair came out as a result of the detangling. Definitely hair that didn't really come out before when I wasn't styling curly and didn't have as many (or any!) tangles.
So basically I'm thinking:
softened follicles (from overconditioned scalp) + vigorous massaging + detangling in the shower = excess shedding = hair loss over time
Definite possibility here.