hello, thanx for your help.

I am male 33 , before 3 months , i have taken a medivation called fevirine , and i stopped it after taking two times , after two days i had a tachycardia and it was the frist time that i feel of that , i got afraid and i went to the hospital and they made me an ECG but it was normal , after that day i started getting afraid of herat attcks and heart problem , i did many ECGs and they were all normal and i made the echo after that then the tred mill , the doctor said it is normal , sometimes i feel that my heart is rapid beatinf and sometimes i feel that it is slow but in the morning i wake up while it is beatinf fast around 105 to 110 per minute , i keep thinking about that and i cant stop i feel dizzy sometimes and headach sometimes , backache and ache in my shloulders , i went to a phycatric and he said that i am suffering from what is called panic attack , i read about fibrillation and i started thinking of two, ( i dont want my phsyche to affect my physcial state , i mean misunderstood by specilaist) . i am a smoker by the way , now it has been 3 moths after that time when i felt that tachycardia , plz advise me what to do and shall i stop thinking about it or shall go to a doctor again or shall i do more examinations. thanx