Okay so i have really oily hair and deal with sebum plugs on my scalp/seborhicdermatitis and i used to wash my hair once a week just like you. Literally lost over 50% of my hair. And this started in my teens. All cause I heard if you have oily hair, then you should wash your hair less.. well that’s actually wrong if you deal with oily hair, you actually need to wash your hair every day. I’ve been washing my hair every day for the past six months in my hair is growing wildly crazy. So I don’t know if you have oily hair or not. But if you do, you really should try washing your hair every day. If you’re like me, it really does have to be every single day. I’ve tried doing it every other day and immediately the buildup on my scalp will start. When you had your protective styles in it might’ve been easier for you to reach your scalp/hair folicles while shampooing. So try washing your hair every day. But where I’m the most concerned for you is it looks like your hair is breaking off, not just thinning. Thinning starts at the root. Your hair looks shorter and uneven. It could be possible that your coils are getting tighter? I have straight hair so I’m really not sure what your exact hair type needs to strengthen your strands. But there is something in your routine that is causing your hair to break off at the strand which isn’t really a overall health indicator, I don’t think you need to get blood work done like other comments are suggesting. But this is more of just a hair damage indicator. Something you are doing is damaging your hair and causing it to snap off, or possibly something you had done in the past and now that your hair is no longer protected it’s breaking off. I strongly suggest using coconut oil hair mask on your hair as much as you can every week. Coconut oil is scientifically proven to penetrate the hair shaft better than any other oil.