I went to sleep pretty late. Next morning i woke up feeling unusual, my heart started beating very hard, at least 200bpm. I felt weak and lightheaded-- i called an ambulance. I had to lay down, i thought i was gonna pass out, i thought i was gonna die. Ambulance came i was brought to hospital. While there my head felt hot inside with no fever, palpitations and whole body sensations like never before. I got out few days later i still felt sick but several days later i started feeling better. Cause for my symptoms was never determined.