Do i have postural orthostatic tachycard

Dear Doctor, I am diabetic for the past 7 years. There is a difference in sitting and standing position in pulse rate. Almost pulse rate differs 30 bpm from sitting position to standing. 30bpm higher in standing position.  I have the following symptoms like very light headedness, difficulty in concentrating, stress, tiredness, while walking i sense light headedness and tiredness. Mild vision disturbance.  My bp is normal, i am taking cilnipres 10 mg bp tablet daily at night. My ECG and Echo cardiagram is normal. My question is do i have postural orthostatic tachycardia syndrome, if so should I worry about this, is it life threatening or any heart related problems? Kindly share your opinion 🙏 Thanks