What Could Cause Morning Fatigue, Nausea, Nighttime Palpitations, And Breath-holding?

Hello. Can someone please provide some sleep medicine advice? I do not have sleep apnea (recent at-home and in-lab sleep studies). I do not snore. In good overall health (thoroughly tested). However, it is very difficult to awaken in the morning, sometimes with a feeling of nausea & dizziness. I feel very tired in the morning. I sometimes wake up during the night with heart palpitations and notice that I am not breathing (Holter monitor showed no problems). I have a tendency to hold my breath while awake. I have had 2 septo/rhino plasties for nasal congestion. Thank you.