The feeling of the heart beat is called palpitations, and this certainly is a common symptom of A fib, particularly if it is also rapid and irregular. Fatigue and tiredness are also common in people with A fib. However, there are some symptoms that are more worrisome and it is good that you are not having any of the worrisome symptoms, including significant chest pain, shortness of breath, or lightheadedness/dizziness.
It is important to note that there are many possible causes of palpitations, and many of these are not serious. A fib is one of the common causes, so it is appropriate to pursue an evaluation, but it cannot be stated that it is definitely present based solely on your symptoms. Obviously, if you have had A fib in the past and this is how you felt, that would be indicative that the A fib has happened again.
Anyone that is having symptom suggestive of A fib should see their doctor, but as long as the worrisome symptoms are not present, it would be fine for this to be done as an out-patient and you can contact your doctor to make an appointment. However, if any of the worrisome symptoms develop, then it is important that you be seen quickly, and it would be better for you to be seen in the emergency room.
If I can provide any clarification, please let me know.