Gmail is from Google
Ymail is from Yahoo
(I have used ymail for at least 3 years, it's not a recent intro. They also have rocketmail as well in addition to yahoo mail)
Different sites, different companies
I have no idea how it could switch from one to the other. I would recommend you change the password immediately in case someone has got in there.
This should help you fix your issue. I would also change my email password asap. Let me know if you cant get this to work or if you have some questions. Its fairly straight forward.
I did that right away CC , still didn't help
Google said my account has been compromised , hence the reason to my gmail going to a Ymail. It only goes there if someone "replies" to my sent mail.
I created a new account but still trying to fix my old one. This sucks, they sent me this link which might as well be in greek http://knol.google.com/k/how-to-reco...m_Your_Account
It may be the "Reply To" entry in your Gmail settings.
Go to the Settings page, then click on the "Accounts and import" and make sure the "Send Mail As" field is set to your correct email address.
Glad I could help! If you need further help or want me to run a virus scan to make sure there aren't any other nasties, let me know through PM's. It's what I do for a living.
I'm actually doing one right now believe it or not.