Please can I have someone’s help? I’m super confused about my thoughts.

Can someone help me please and shed some light onto something that has happened?

So, I wrote this already but I wanted to shorten it. But basically, a body was found near my area (stuff like this doesn’t usually bother me, I’m not sure why but it’s none of my business really). But, this made me feel eery. Then suddenly out of nowhere I had an overwhelming feeling that something had happened to my ex (we aren’t in contact atm, but still friends). Deep down I knew nothing had happened to him but I couldn’t shake the overwhelming feeling. I was shaking and was super anxious. I’d also checked his social media to be safe. 

I thought that I’d sleep and it’d be okay. But I slept terribly and when I woke up, I still felt super anxious, which led to me not being able to breathe, shaking and a lump in my throat etc, just crying loads. But also being aware I was not being practical. 

I’ve legit never had this and I’m so confused. Why did it affect me that much when I knew he was okay and in no harm?