Feeling of suffocation

[Dendenten]

I'am 14+ age and i feel suffocated while breatging . I'am not on any drugs for any disease but recently i have been feeling this uneasiness while breathing. I  suddenly start feeling suffocated and sweat starts to form . I feel  dizzy and cold at the same time when I am felling the suffocation . But no matter how dizzy I feel I do not faint . It stops somehow automatically. When I did the blood test the doctor told me it is due to lowhaemoglobin which was a problem I faced as a young infant too. Please help me in this matter i really need help.
               Thank you .