This is just a random little piece of advice.
It is so easy these days because of the Internet to type in certain symptoms and find different disorders and sicknesses. People can convince themselves of having all sorts of diseases. Trust me, i've done it myself. I'll get sick and type in the symptoms and be thinking, "oh no! some of those symptoms fit under 'this type' of illness". One time I convinced myself I was pregnant, and I had never had sex. It is amazing what the mind, and a 'little' stomach pain can do.
Especially for someone suffering from anxiety, it only adds to the problem. Those with anxiety and especially panic disorder can experience a wide array of symptoms, whether during attacks or at other moments. Just take this advice: every time you feel a different bodily sensation, don't let it worry you. Don't keep checking your pulse to see if it is beating regularly, as this can increase anxiety. It could help to think about the odds of actually getting the disease you think you may have.
A way to ease your mind is to live a healthy lifestyle in order to decrease health anxiety. Exercise is so helpful for individuals with anxiety. Yoga and deep breathing exercises are great too. Try to live as active a lifestyle as possible, and spend less time researching on the Internet. Go for regular check-ups at the doctor. Eat healthy.
My mother used to know someone that would carry around a medical book that listed different diseases and she would convince herself of having a new one almost every doctor visit. The doctor told her to throw away the book! You can't throw away the Internet, as it is right at our fingertips, but you can control what you choose to look up. Instead of researching and adding to health anxiety, tell yourself to stop and do something productive. Easier said then done, but try it.