Hi John,
Many of the symptoms you're describing like fast metabolism, irritability, and anger can occur in hyperthyroidism. The most common cause of hyperthyroidism is Graves' disease, which is an autoimmune thyroid disorder.
Here, symptoms can wax and wane, or come and go, for extended periods. And periods where there are flares of symptoms can alternate with periods of remission, where no significant symptoms occur.
One of the most common triggers for Graves' disease is stress. Hyperthyroidism is fairly easy to diagnose with blood tests. It would probably be a good idea to ask your regular doctor if you have one to run thyroid function tests. If you don't have a regular doctor, you could see a general practitioner or a family practice doctor.
You might also be blessed with genes that keep your metabolism high and some of your other symptoms, including anxiety, could be related to stress. Stress is responsible for many health problems and symtoms that interfere with well being. While exercise and diet can help in dealing with stress, it would be good to have your thyroid levels checked to be on the safe side. Best, Elaine