I'm sorry to hear you are having these problems. I also have anxiety. My worse fear is leaving my kids. My oldest is on his own now but I was a single mom with him. But I know have a 9 and 11 year old and when times get tough thats one of my main problems worrying about leaving them without a mom. I have to try and push it to the back of my head. The worse is the night time when you can't sleep and the thoughts race. It does sound like you are having anxiety. Go to your primary and get everything checked and it he or she says everything is fine talk to see what they want would recomend for anxeity. Good luck I know how hard this is. Keep me posted.
Panic attacks can very well feel like a heart attack! they bring on horrible fear and symptoms. I have had them for 20 years though they seem to finally be under control most of the time. I have found that cold water and putting a rubberband on my wrist and snapping it seems to break the fear and panic as our minds can only control the sensation on place at a time.
If they sent you home I am sure all is well. I deal with bad anxiety too and it is horrible I also would have your thyroid levels checks I have thyroid hashimotos and it diffently brings on my heart palpitations and anxiety bad when they are out of whack, like they are now. I hope you feel better , I understand and share your pain, I too have little ones a 14 month old and 10 yr old at home, my worst fear is leaving them so young with out their mommy. If you need to chat I am here!