doctors can't give me a solid diagnosis.

When I have episodes I can hardly feel my heartbeat, I feel my body pulsating, my body is heavy, im gasping for air, I have a hard inhale and heavy exhale, like its hard to breath and i cant move. It happens at random times however, most occurrences have happened while just waking up. I feel like my heart may be giving out. My whole body feels like 10 times my weight has been put on me. I've had series of tests including EKG,EEG, X-rays of my torso as well as my head, Countless blood tests, urine tests, auditory tests, visual tests and more that I really can't remember right now. I had been to constant follow-ups and eventually stopped going because there were no answers and it was tiring. I've researched and noone seemed to be going through what I was so I was again In a dead end. Could someone please help me and give me answers or even educated guesses. It would be geatly appreciated and thank you so much for your time.