Taking a new medication can be scary and you may be looking for signs of a problem.....Being acutely aware of your body and the most subtle changes, such as an increase in heart rate, can be a catalyst for anxiety... for example.. heart rate goes up.. you become aware of it and get anxious, and it goes up more. This is a normal response to anxiety.
The scary thing about Anxiety is that it can seem to come out of nowhere.. without a concrete cause that you can pinpoint. Anxiety can cause alterations in breathing patterns and it may be that you are holding your breath or breathing too rapidly which can cause fatigue and the symptoms you are experiencing. There is something you can do right now to stop it..... initiate proper breathing. You can help alleviate the feeling of throat tightness, panic and and shortness of breath by changing your breathing pattern to abdominal breathing. To abdominal breathe ( which is a much more effective breathing technique) place one hand on your abdomen and one hand on your chest... watch to see which rises. It should be the abdomen, NOT the chest.Practice breathing using your abdominal muscles... (to breathe with chest muscles causes fatigue and more shortness of breath) by taking in a deep breath through your nose.. making sure only the hand on your abdomen moves, slowly.. and exhale slowly through the mouth.. your abdomen should flatten with exhalation. Do this three breaths at a time. Breathing correctly will immediately eliminate anxiety...., every time. If it comes back do it again. Here is an excellent link to read more about anxiety:
Consider taking extra hydration ( atleast 8 glasses of water per day), this will help as well as de-stressing through the use of biofeedback and relaxation techniques ,
definitely plan to get adequate sleep. Sleeping is so important for over all well being.
Here is an interesting article and video:
This article explains why incorrect breathing causes anxiety symptoms:
Also look for EASY CALM by John Mercer video series on youtube.. John Mercer has some excellent techniques.