Thank you for your message and I am sorry to hear you are suffering with these challenging symptoms.
Generally an anxiety disorder is characterised by recurring, more pronounced or longer lasting bouts of symptoms and health issues which give rise to feelings of anxiety, as opposed to brief feelings of nervousness or stress which most people suffer from at some stage in reaction of life situations.
Another more simple cause for some of the symptoms you describe below can be blood sugar dips and dehydration. If we eat irregularly, leave long gaps between meals, consume too much sugar, processed foods, alcohol or caffeine our blood sugar levels rise and fall too quickly. This can cause mood swings, lethargy, heart racing, feelings of anxiety, shaking etc. Drinking insufficient water or hydrating fluids can also cause similar symptoms.
Anxiety is also a bit of a vicious circle, if we worry about it, it causes more anxiety so it is important to deal the symptoms by visiting your GP to help determine the cause and rule out any other health issues.
Once you have seen your GP, should you wish to follow a more natural route, you could consult with a Nutritionist or Medical herbalist to discuss the best course of action. Follow these links to find a practitioner in your area (www.bant.org and www.nimh.org.uk)
Do come back to me if you have any further questions and rest assured there are many helpful techniques to deal with symptoms of anxiety but it is very helpful to understand initially, what the cause may be..