Hi Klapaucius, and welcome.
I was waiting for one of the hyperthyroid folks to post in reply to you, since they'd be better able to address your concerns. Hyperthyroid is not generally lethal but should be treated.
Hyperthyroidism is a condition where your body is producing more thyroid hormone than it needs. Symptoms include racing heartbeat, anxiety, hot flashes, the inability to gain or hold a steady weight, etc.
Don't panic. There are many people with this condition, and some excellent information to help guide you on your way back to good health. A thoughtful Endocrinologist can explain what you can expect and how to treat your particular case.
Diagnosis is made by blood test and review of symptoms. It is best if your doctor tests Free T4, Free T3, and TSH to get a balanced picture of how your body is behaving. These tests are typically repeated every 2-3 months during your treatment to determine how to maintain normal levels in your body.
Click on our Information Archive thread for a good basic education on thyroid disease. Read through the hyperthyroidism checklists to give yourself information to review with your doctor regarding your symptoms. <A HREF="http://www.healthboards.com/ubb/Forum118/HTML/000005.html" TARGET=_blank>http://www.healthboards.com/ubb/Forum118/HTML/000005.html</A>
Another great site is About.com's thyroid section. There is a lot of good info here, but you can start at Thyroid Basics/Thyroid 101 and the Hyperthyroid links: <A HREF="http://thyroid.about.com/cs/hyperthyrdgraves/" TARGET=_blank>http://thyroid.about.com/cs/hyperthyrdgraves/</A>
Another favorite is EndocrineWeb. Click on the Hyperthyroidism link and read through what you need. <A HREF="http://www.endocrineweb.com/thyroid.html" TARGET=_blank>http://www.endocrineweb.com/thyroid.html</A>
When you're done with the review, let us know how you're feeling, what you're experiencing, and ask lots of questions. The return to good health is a slow process, but it will happen. We're here to help and support.