So would anyone have any idea why my ends are really thin?

My hair has been shedding a lot lately (mostly b/c something is causing me a LOT of tangles, and when I comb it out in the shower, I lose alot) - so while the volume of my hair is thinner, the ends were REALLY thin - not split, but they don't look good so I'm cutting them all off.

It seems when my hair gets past BSL, I get these super thin unhealthy looking frizzy ends. Help?
3b/fine/normal porosity/normal elasticity

LOVES behentrimonium methosulfate
(don't ask me to pronounce that!)

Want to grow it long again!
And simply want to figure out this hair of mine!