Ammonia like smell when deep breathing. and lightheadedness for 3 days all day without movement. no other symptoms. what could it be? please.

Working out: If you are working out too much or burning too much fat/protein due to diet or work out it may produce ketones that are breakdown products of fat/muscle. This can give the ammonia like odor. Starving can do it too. Some fat burning supplements can also do this. Make sure you have some basic blood work for kidney and liver function testing done, because it is not normal to have the symptoms you do.