Ever since i've been diagnosed and treated.for hypothyroidism i have been losing my breath(gasping for air) and i can't do 30 seconds of exercise.help?

See your doctor: If you thyroid is properly treated, you should not be short of breath. You need to have this checked out.

Not thyroid.: Doesn't sound like this is related to your thyroid unless of course it is very large and impinging on your airway. You didn't mention this so i don't suppose that is the issue either. You have another problem which may be anxiety or possibly a reversible obstructive lung dysfunction such sas asthma.