I filed my taxes back in March and still haven't received it. It's been saying ready to mail for 6 months. Can you please help me to find out what happened?

 Sorry but Ready to Mail means you have to actually print out your tax return and mail it to the IRS yourself. So it has not been filed yet. You can try to switch to efile https://ttlc.intuit.com/replies/3985787 

Or did you mail it?  Turbo Tax will always say Ready to Mail.  They don't know if or when you actually mailed it and the IRS and state don't tell Turbo Tax when they get mailed returns.

Did you file a state return too?  Federal and state need to go in separate envelopes to different places.  I've been seeing people say they mailed both in one envelope to the state.