Losing hair

So for a few weeks now the amount of hair I lose is increasing by a lot. It’s all coming from my roots and I don’t understand, the top of my hair is healthy untouched and I don’t apply heat to it. I haven’t been more stress lately. I’ve actually been less stress. I have thick hair so It doesn’t look like I’ve lost much but the amount is increasing and I’m afraid it will start to show. I just turned 18 I’m still young.

Here’s from one brush of my hair. Before I brushed it I took a shower and lost a lot in there so it would’ve been more. I know the ends of my hair are unhealthy but the the rest of my hair is healthy I know the rest is fine. Anyways this is not a normal amount of hair loss for me. I don’t know what to do.