awful / awfully
The adjective awful, though often used informally to mean "very bad," is (like very had) too vague to be effective. Use a more concrete or specific term.
The adverb awfully, used to mean "very," is similarly overworked and (like very) should be either deleted or replaced by a more descriptive expression.
By the end of the day I was awfully tired.(exhausted)
I am awfully sorry.
awhile / a while
Awhile is an adverb and is not preceded by a preposition. A while is a noun phrase. It may be preceded by a preposition (usually for or after); its noun, while, can be modified by an adjective.
Wait awhile before calling again. [The adverb awhile modifies the verb wait.]
BUT Wait for a while before calling again. [The noun phrase a while is the object of the preposition for]
We waited for a long while before calling again. [The adjective long modifies the noun while.]