Annoying VOCAL PROBLEMS!

So this particular issue keeps on reoccurring and it honestly make me wanna stop recording all together. 

So I record all of my vocals over the backing track, 100% complete the whole song, Harmonies all.

So I play it back to listen to the WHOLE  of it before mixing it down, Then OUT OF NOWHERE!! 

My voice sounds like a Child!?!?!?!

It's in the EXACT key I sang it in.... BUT IT'S BABYFIED MY VOICE!

And I have NO IDEA how to fix it. 

It's happened 3 times when each song is 100% complete.

I go to listen to it ALL 1 Last time.

Can somebody please help me fix this please 

Adobe Audition 3.0 has been doing this to me for too many years man.

Makes no sense, as the key is EXACTLY how it was sung.... But just a really Childish tone, Same thing happens to the Instrumentals being used as well

Thank you