Is thinning hair also a sign of hair loss?

I compared old photos with recent ones.
It felt like my hair itself had gotten thinner, rather than just having more volume.

Especially when I touch the top of my head, it feels weaker than before, so it bothers me for no reason.

It's not like the amount of loss has increased significantly.
I also wonder if I really need to worry about hair loss with just this much.

If there are any of you who have had an examination after noticing a change in hair thickness
I'm curious how you initially verified this.