When trying to sleep, head becomes heavy, ear ringing, fast heartbeat, excessive saliva, difficulty breathing. What's happening to me?

Breathing problem. You should be seen at the emergency room to rule out a heart problem. Do not wait on this.
Diet, exer, stress? Can you share in comment what you tend to eat or drink in the evening? I can then help provide a better answer. Addendum from member: "sometimes i eat early and still get these symptoms. I started a vegetarian diet a month ago and i'm not getting sun exposure cuz i'm at the office all day. " (see comment.).