I haven't had those symptoms (maybe the heart pounding). Anxiety can present in weird ways though. How often are the muscle twitches? Don't go looking your symptoms up on the internet!!! Just see a doctor if you need to, but what ever you do--again don't look up stuff.
Therapy might not be a bad idea. A therapist can teach you coping skills and ways to deal with your anxiety.
I also agree that you should NEVER research your symptoms on the net. The internet is a great source of information but not for medical diganosis.
As for the twitching it could be a condition known as Benign Fasciculation Syndrome (BFS). It is a benign twitching disorder and it can't hurt you it is just really annoying. Stress and anxiety make it worse and it can happen in pretty much any muscle throughout the body. Sometimes it might only last for a few seconds other times it can last for days. I have it and I was diganosed by a neurologist. I am not a dr and I am not saying that is what it is. Seeing a neurologists might not be a bad idea either.
I hope you start feeling better soon....