How to stop freaking out over your cat's wellbeing?

I tend to freak out whenever my cats hit their heads, land awkwardly or when they start doing something out of the norm for them. For example, a few minutes ago one of my cats hit her jaw on my laptop while I was working on some job applications. I freaked out and did a full body and mouth check to make sure she was OK and she was, as she was happily eating away her kibble just a few minutes ago. Or when I step on their tails by accident I need to pick them up and run my hands through their tails to make sure they are OK.

How can I stop being so fearful and worried about their wellbeing all the time? I even think about how they are doing at work and I make sure to make my flat as cat friendly as I can. I never leave any toxic substances within their reach, I make sure the floors are clean so they don't eat anything dangerous, the cleaning products are locked away from them. I treat them as my children.