It sounds like a medical condition, so the best people to treat it would probably be trained doctors. If the ER doctor didn't examine you, you might try seeing a different doctor and getting a few opinions.
Weight is probably an issue.
It might have something to do with your sleep if you are tired all the time - maybe sleep apnea
It might be stress
related, and maybe some type of panic attack
At any rate, a medical doctor
is really the one to see.