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There appear to be two different issues? - though they may have a common cause...
You have not stated your age or gender.. You didn't say other symptoms like tinnitus
/ or associated diseases. Smell has no direct association with giddiness.
You ought to see an EAR Nose Throat specialist for favour of further assessment - the mechanism for balance is in inner ear
... He can also check the issue of smell
You may need MRI
of the brain. A NEUROLOGIST
may have to see in view of the smell and spell....
Wishing speedy recovery