A loss of smell could mean a number of things.
For example, you might not be able to smell scents you normally can (anosmia).
On the other hand, you might start to smell things that aren’t there, such as burnt toast or smoke.
This is called phantosmia, and it can also affect how things taste.
Phantosmia is normally caused by an infection such as a cold, flu or sinusitis.
Phantosmia may also be caused by growths in your nose, epilepsy, migraines, and other more serious conditions.
However, if this persists, see your GP.