Although stress may cause shortness of breath
but still you must rule out other causes for tis breathlessness.
Get your lung function test to rule out bronchial asthma.
Consult a cardiologist
and rule out heart involvement.
Get your thyroid function tests
done to rule out hypothyroidism.
Your hemoglobin levels are low but it may or may not be the reason in you.
Pending your testing as advised above start taking B complex vitamins and iron supplements