Extreme hair loss

I’ve lost so much hair and my hair has thinned out so much it’s so depressing. It’s been like this for months and before the diagnosis (when I had no idea I was diabetic) i thought it was from slicking my hair back too much for work. My hair texture is thin and brittle and I’m losing it by the clumps every time I wash it. I’m feeling really discouraged.

Does anyone have any recommendations for this?? Shampoos / conditioners ?? Should I start taking Biotin again?? Help