Hi,Welcome to Health care magic forum.
It appears to be due to the anemia
, and less oxygen
carriage. The other causes may be the gastric irritation,anxiety
I advise you to consult a physician for diagnosis and treatment.
You may need to have E.C.G, echo, and stress test
. to exclude the cardiac involvement.
Take more of green leafy vegetables,pulses,sprouts,and protein rich foods to have blood,general health and resistance against infections.
Wishing for a quick and complete recovery. Thank you.