Anne, a lot of people don't understand fibromyalgia...even some doctors. It sounds like the anxiety is what is causing you many of your problems. Anxiety is caused by fear and can cause depression, too. You really don't have to fear fibromyalgia. You just need to face it head on and learn how to control the pain. We can help you there!
You do need to keep moving and I'm sure your autistic child helps in that department! I have a four year old autistic nephew so I know it isn't easy for you. Check out the Fibro 101 thread...the second thread on the forum. There are links to good info about fibro...including some good stretching exercises that really help.
You need to work with your doctor about meds that help with the pain. I'm on ibuprofen with food and Tylenol for pain. I also take malic acid/magnesium supplements for pain and fatigue. They don't help everyone but many members have had good results with these...including me. There is a link in the Fibro 101 thread all about them and how they work in your body.
If you are concerned about your heart, have your doctor run tests to make sure you are healthy. I did that when I started getting palpitations...another symptom of fibromyalgia. After having a few non-invasive tests I don't think about that anymore. It's the anxiety that is causing you to panic over every little thing. I went through that many years ago but now, when I get those anxious feelings, I recognize them and get busy doing something and the feeling leave.
We are here to help you. Try to relax and get control of your pain. You can live a full and enjoyable life with fibro!
Sherrine