Anxiety issue heart palpitations. Only?

I am facing extreme feeling of worry and tension from month of April. Started developing breathing issue that time. I have consulted my gp and done all test thyroid sugar hemoglobin cbc all are normal. Ecg detects sinus arrhythmia. I am now presently on tapering dose of metxl 12.5. once a week after consulting my gp. But my concerned is that I get frequent anxious episodes with sudden high of pulse rate body heat,sweat and tremors body trembling nervousness.Sometimes with headache that I feel my pulse rate on my head too. And my heart pound too fast and left arm shoulder pain ,nausea loss of apetite but I dont feel any severe pain in my chest very rarely I feel some mild pain in chest part dont know may be due to anxiety.I try to free my mind but this thing is just became a part of my health.Not leaving me. So as I have done my ecg on june. Do I need another heart check up? Or it is due to anxiety only?I am very much puzzled with my feelings.