My manager never responds back to me when I message them I’m sick. Why?

I know it’s small, but I’m sick today and couldn’t make it in. I messages my manager, told them I’m not feeling well, not going to make it in. Told them I have everything covered by coworkers. I get no response back. This is the 3rd time this year it’s happened (I’m not sick much), and it kind of pisses me off.

Do they just not care? Do they just not believe me? It’s the small things for me, and kind of rubs me wrong. Maybe I’m just being soft.