Can I recover my iTunes songs after changing my email?

Since Apple moved from iTunes to Music I lost my library of bought songs and albums. Probably due to the change of my email address. I can't log in with my former mail-address and my current Apple account only works with my new address.

This may legit bought music and I want it back on my own harddisk.

Is that possible?

[Re-Titled by Moderator]

Original Title: Lost my iTunes songs since my new mail