I'm new here too. Bit scary putting it out thete at first isn't it.
I'm a 47 year Dad to 3, just reading your post struck me as I think I suffer with anxiety, as yet undiagnosed by a professional.
I do the same, a sense of panic and fear if one of the kids feels ill. I stress when they go near a swimming pool or play park, I constantly imagine the worst, whatever the scenario. In my mind I can make the most innocuous situations seem dangerous.
I'm thinking of finding a counselor, somebody suggested it on here, perhaps we can just get a referral from our gp.
I hope you can find a way to speak to someone about this, when I wrote my first post and someone replied, with some really kind words I didn't feel quite so alone, somehow it seemed a bit better.
It's stressful enough being a parent, adding this sort of complication makes it infinitely harder. I'm so sorry to hear your husband has been diagnosed with a heart condition, it sounds like your dealing with a lot at the moment.
I'm going to investigate counselors and the costs associated with them, or if there's some sort of community based service, I'll let you know how I get on.
Good to see you found this forum and found the courage to put what your feeling out there. Hopefully someone with far bettter knowledge and experience than me will point us both in a better direction.
Take care for now.