Thanks for the query.
During early mornings there will be some amount of fluctuation in the hormonal
levels, especially in thyroid
And that can lead to some metabolic alterations. So the symptoms you are experiencing could be sue to that.
And also some people can have hypoglycemia
in the morning.
As you said stress
and strain can also lead to breathlessness, increased heart beat etc.
If the symptoms persist once consult physician and check for hemoglobin
levels, blood sugar levels and thyroid profile. If needed go for ECG.
Don't worry there may not be any major problem. These tests are only to rule out the possibilities.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429